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Reef miles long (1) broken through by beached beached passages.— the eye parallel lines — internal from of land cocoa nuts: (2) — circle of Hills — breadth where narrowest at low water nearly 30 yards — broadest rather more than 60 — country points 80 — does not vary suddenly — deep water close inside ships moved very strong currents from [illeg] bays & rivers at old guns let in — enough for 2 & 3 or turns ship to the outside turbid water gradual shoal — covered at high water spring tides, about half tides a man can walk along whole length; on inside at low water nearly 8 ft can be seen all same constitution.— — [sketch]

Inside fallen cliff; sandstone fine grained (3) siliceous particles brilliant (cement?) — merely a slightly ferrugineous fragment of shells, many scattered pebbles of white quartz like beans & smaller, viz few as large as egg — no structure scarcely visible.— one seam as thick as dollar, of [illeg] Carb of Lime.— surface weather very unequally; minute points, & base obscurely circular — great rectangular fissures which hair allowed parts like contraction in freezing of glaciers to subside & fall off.— former especially on outside forms irregular strips.—walking away after substance — some softer substance beneath. In only extent on inside, an oblique [illeg] beneath amorphous; up 45 slightly saucer shaped.— appeared modelled on inside of a bank.— generally way into cliff with subsided fragments — Surface both generally (excepting from unequal decomposition smooth & level — Slopes slightly seaward but in a few parts really level or I imagined dip

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inside, where broad the reflex outside last longest hence slope must outside in such parts: surface (pebble so abundant in parts as to form a shingle bed) on flat surface, pebbles have a pedestal as if wearing away.— curious sinuous little channel 2 or 3 inches wide or deep. 6 inches to 2 ft long, sometimes branch off rounded exterminates.— longest being transverse, to far, edge overlapping — a joint action of transverse surf? & structure of sandstone.—

Near high water sea mark over as in time Coral reed general resemblance excepting on inside cliff = on the out their cavities thickly lined with associated actina (slight, coral calc formed within such pits) & Balanide of (two species) in numbers on points, all help to protect # on outer subsided ledges, which is washed by spray during the greater part evening tide, there is coast of soft calc layers (full of worm holes (& cases?), formed chiefly an obscure dull red thin Corallina, (& as part) is aided by Balanide & other objects — Thinly could with curious tuft of minute algae, conferva & associated Actineæ.— when basal sandstone worn into sinuous cavities, be  thin calcareous ridge incur leave form a reticulate rock = soft = on the most exposed point although not hard, yet resists hammer singularly in these petrified well; must be then of some thickness — gradually thin away in higher & central parts.— Extremely rarely a point of sandstone (when surrounded with this matter for many yards) shows what is the base.— Showed that the sandstone is not a mass thrown up behind a coral reef.— sandstone appears like true subaqueous deposit (=) this structure non calc layer would not be produced with present forms

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elevated.— How strange that turbid water constant violent surf should not degrade sandstone. — (allow dead & living [illeg] , yet in parts worn away!!

Gales & pebbles & Chemical action — There are cliffs 4 ft high exposed to full force of waves oc in the narrowest part of reef = it is consolidated, elevated sand bank protected by same agency which protects coral reefs = It is the least! difficulty solid stone & cement being formed at surface & within violent spray!—

If there is any stratification it is seaward except to the oblique seams (which are seen at dead low water for space of 700 yards) not conformable to surface subsidence & rectangular position gives artificial aspect = Outgoing points very rare, probably peak of sandstone wall covered with the most solid calc layer.— Vegetation or mawn peat, is here (as soil on land) only conservative.— The cavities something like what is produced in Coral reefs

Outside reef by ledges sinks suddenly.— at the distance of 21 1/2 miles about 12 fathoms & commonly on this coast (Roussin) at 9-10 leagues 30-40 fathoms so shoal very gradually.— bottom at the 12. (& under) rounded grains of quartz.— small pieces of shells & great quantities of dead & living bits of red-inarticulate sub-branched Corallina!— Roussin, general character of bottom: In the offing bottom chiefly minute brown calcareous sand: where particles, appear the result from organic bodies, but it is hard to say whether from shells th Coral [illeg]

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(1) I did not examine reef for more than a mile: could see it was similar far more than another.— In Roussin charts the same form of reef is continued for many leagues to the South; below Cocoa nut tree Isd it runs within 100 yrds of the shore; though generally straight, it bends round some abrupt headlands in perfect conformity: (2) on low banks on which town stood loose sand, but in neighbourhood, if low water a considerable quantity of sandstone is quarried, differs from that of reef, in lesser hardness only in containing numerous fragments of shells, such which appear to be sand as how live is this same waters. (3) I note Books constitution of sandstone calcareous cement owing to dissolved shells = Very strong current at base of inner wall = The principal ingredient in the protecting coast is the Serpulaæ: one specimen shows effluences of the Corallina = Extreme straightness a remarkable feature =

For height of coast v. geolog: Brazil.— B. Roussin states that whole coast from a little N. of Cape Frio to mouths of Maranhan are skirted with reefs.— the structure of them without doubt varies much .— north of Bahia from what I saw. I believe it mainly consists of a flat extended recent aggregation of sand & pebbles: & in the charts on a large scale it is represented in a very different manner (+).— (at pagination 10 derail reef) in mouths of many of the rivers, perfectly similar bars, for there are bars with channels fronting every one.— Even South of Bahia at Porto Seguro, there is a quay somewhat similar to that of Pernambuco. But besides these bars there appears to exist true coral reefs which are united on to the extremities of these consolidated bars & so form a perfect barrier (+ In the northern parts so perfect are the reefs that they leave are more perfect & more properly design their name.— From P. Francez passing Pernambuco to R. Parahyba Parahyba delta note a distance 180 geograph miles.. small vessel 2 or boats 1 can pass within the reef having generally 10-12 ft of water Roussin.)— I was informed by an intelligent gentleman Captain of a merchant vessel, who had examined both reefs at Pernambuco & at Port Francez 3 near Alagoas that they are extremely different at Maceio the latter place there is no sandstone, but at low water outside the living coral may be seen which may be turned into the white stone of which the reef is composed. The reef is described as about 100 yds but very irregular wide; it is dry at low water

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4) but is covered at the high water.─ it is full of great irregular cavities & holes so as to render it very difficult to make over in which the water rises & falls with the waves outside ─ The external parts are most solid & the inside most full of holes.─ The reef terminates in front of a large bay to the north in runs 5 or 6 miles skirting the coast is commonly about 3/4 of mile distant, this water very shoal, averaging about 12 ft, with a sandy bottom.─ The deepest part is near (but not close) to the reef in one such part of that there is four fathoms & there ships lie.─ In some part of the coast the reef is 3 miles distant from the shore.─ It is evident these reefs resemble those of Mauritius or true coral reefs.─ I came to the conclusion that there greater part of their long lines of reefs must be Coral before hearing of these facts, if it ever should be proved otherwise, it we must then imagine, that there is a tendency from the reflux of the waves to throw up a bar along a whole line of coast.─ In these northern parts, where reefs are most abundant, the water shoals very gradually, at the distance 9-10 leagues generally 30-40 fathoms water, but at twice that distance no bottom with 120 fathoms.─ Further South, in front of neighbouring country of Bahia the water is rather deeper at a distance of only 9 leagues somehow no bottom with 120, & sometime with it or with 200; yet this geologically is very shoal in a plain 27 miles long, who could appreciate a rise of 1200 ft. The rise from the sea to Lima being 500 ft in 6 miles is quite inappreciable

The soundings in all the part now alluded to is generally sand with minute broken fragments of shells & corals; the quantity of the calcareous particles seem most abundant in the offing which might be expected from their great highness & consequent faculty of transportal. Roussin

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states that from the Abrolhos to nearby Maranhan, the bottom in many places a "tuf blanc mêles ou formes de madrepores broyes." [p. 101] this matter is sometimes firm & he compares it to mortar.─ it probably resembles the bottom in the deeper holes of the lagoon in the keeling Isds. This fact would alone render probable the existence of extensive coral reefs rather than sand bars along the line of coast.─

Beyond the bank of unequal breadth, but yet always considerable the water appears to deepen rather suddenly; here we must attribute the origin of the bank to the limits of currents carrying the sediments.─ the thickness of their deposits is probably pretty uniform for a breadth of at least 30 miles. Their nature must differ the Calcareous & Calcaires — sandstone which we may believe are now consolidating into as hard rocks at least as hard as those on the coast; in the parts S. of C. Frio M. Roussin states that mud is the more usual kind of bottom but yet mingled with fragments of shells & corals.─

NB Horsburgh nothing about coast of Brazil