362 



DESCRIPTION OF THE 



pally, by No. 613, and patches of shingle. In the bays, for a long distance above 

 the Bay of Islands, this rock appears to bear east of north, and is seen at all the 

 small points, and at the bottoms of the pockets, as far as the first island, which is 

 composed of it. At several places it seems to be bedded, and to have overflowed 

 the sedimentary rocks through which it was erupted. At the second point, above 

 the mouth of Little Cedar River, No. 603 is seen, carrying with it, as before, huge 

 embedded masses of felspar rock, and lining the shore of Cedar River Bay. The 

 easterly point of the bay is made by No. 613. The islands between this point and 

 the Great Palisades, with the exception of the one already noticed, are composed of 

 No. 252. 



Judging from the direction of the islands, and the line they make with one 

 another, as well as with the shore and the Palisades, I set down the bearing of No. 

 252 at north 10° to 15° east. The shore opposite the islands is made by No. 603. 

 In the bottom of the bay, above the Great Palisades, and between that and the 

 islands, metamorphosed sedimentary rocks are seen underlying No. 603, which 

 forms the small points that give so much irregularity to the shore here, and has 

 embedded in it large fragments of felspar rock and of a greenish-coloured trap. At 

 this place there are two, if not three large dikes, belonging to the different periods, 

 and differing in mineral composition, yet having nearly the same bearing. 



In the deep pocket, at the beginning of the Great Palisades, is a dike of No. 624, 

 bearing north 45° W., traversing No. 625. The Palisade rock here overlies a very 

 finely-laminated slaty rock, much altered by heat, and associated with a brecciated 

 conglomerate (Nos. 627 and 628), which is interposed between the altered slate and 

 No. 624. It is amygdaloidal, and presents the appearance of having been partially 

 fused. Both the cementing material and the pebbles, which are rounded, are 

 equally full of small cavities, most of them empty, but occasionally filled with par- 

 tially decomposed zeolites and other minerals. The degree of fusion to which the 

 rock has been subjected was so great as to produce a very complete blending of the 

 pebbles ; still the difference in degree of fusibility of the various rocks from which 

 they were derived, as well as the differences of composition and colour, serve to 

 mark its regular conglomeritic structure with the utmost distinctness and certainty. 

 At this exposure the conglomerate is about forty feet thick, exceedingly rough and 

 irregular in fracture, soft in some places and hard and brittle in others. It is tra- 

 versed by veins of quartz, calcareous spar, and oxide of iron ; all thin, and seeming 

 rather to fill joints. Parts of the rock resemble very much the amygdaloid, under- 

 lying the basaltic trap before spoken of; and this is especially the case at its junc- 

 tion with the Palisade rock, which, as before stated, rests upon it. 



The Palisade rock (Nos. 250, 251), specimens of which were taken from the 

 bottom and top, present, essentially, the same characters throughout. It is gene- 

 rally of a brick-red colour, very hard, with a sharp, irregular fracture, and contains 

 numerous small crystals of quartz, and many of decomposing felspar. Great 

 numbers of minute quartz veins also traverse the rock, crossing each other in all 

 directions, and producing a very beautiful reticulated structure. The following 

 sketch, by Major Richard Owen, presents a very accurate representation of its 

 appearance, as seen from the Lake. This rock rises from the margin of the Lake to 

 the height of over three hundred feet, presenting perpendicular columns from sixty 



