152 INDEX TO THE STRATIGEAPHY OF NORTH AMERICA. 



D. 



reet. 



1. Greenish-white and yellowish-white magnesian limestone, in massive beds, some of which 

 are ferruginous and weather buff, while others remain unchanged in color. They are 

 interstratified with beds of ash-gray limestone, weathering yellowish, and near the middle 

 with two bands of gray* calcareo-arenaceous shale, one of 2 and the other of 3 feet thick. 

 These massive limestones terminate in a 4-foot bed of smoke-gia,y pure limestone in thin 

 layers, interstratified with thin layers of probably magnesian limestone, weathering ocher- 

 yeUow. The bed', for the thickness of a foot, is arranged on the strike in a series of curves 

 or arches, which span from 2 to 3 feet, separated by straight intervals, varying from 1 to 2 

 feet. The curved portions appear to hold a greater number of the yellow-weathering layers 

 than the straight parts, and these layers have in general a lenticular form. The top and 

 bottom of the bed are arranged in even layers, which fill up the inequalities of the inter- 

 mediate part 174 



483 



The surface between East and West bays rises into a mountain of 500 or 600 feet in height, 

 in which the strata dip in directions conforming to their synchnal arrangement, at angles varying 

 from 12° to 25°. Proceeding southward along the east side of West Bay, they are seen to 

 accumulate above one another to the amount of 1,400 feet, in addition to the preceding section. 

 These higher strata consist almost entirely of limestone of various shades of gray, with two or 

 three bands of black, the latter usually thin bedded. Of the lowest 200 feet, about two-fifths 

 weather to various shades of yellow and brown; of the succeeding 300 feet the proportion of 

 yellow- weathering beds is about one-sixth, and in the remaining 900 feet they are but few. If 

 these yellow-weathering beds are, like the similar ones in the detailed section just given, mag- 

 nesian, it would appear that the proportion of magnesia gradually diminishes in ascending 

 this portion of the series. In fthe whole of these 1,400 feet, which are supposed to represent 

 the divisions E, F, G, the only strata in which fossils were observed occur at about 400 feet 

 from the top; where the surfaces of various beds, in a thickness of between 10 and 20 feet, are 

 marked by the weathered-out forms of silicified fossils, consisting of undetermined species of 

 Pleurotomaria and Ophileta. 



From West Bay the strata strike, in a general way, along the coast to the westward; they 

 are much contorted and it is difficult to make out any true continuous succession of the beds. 

 At the west horn of the bay, however, the whitish massive magnesian limestones of division D 

 occur; and in the contorted strata for a couple of mUes beyond the peculiarly striped smoke- 

 gray and ocher-yellow thin-bedded limestones of C 13 are occasionally seen. At the promontory 

 Which faces the west horn of Deer Brook Bay the strata become vertical, or nearly so, but 

 somewhat more regular; and the absence of any beds weathering yeUow or brown appears to 

 indicate a proximity to the horizon of the silicified fossils above mentioned. About 800 feet 

 of dark-gray limestones are here exposed, at the summit of which there occurs a bed holding 

 Maclurea, Orthoceras piscator, and Leperditia. Of the genus Maclurea the opercula were the 

 only partp observed and these are silicified; but the bed is supposed to be higher in the series 

 than the band with silicified fossils between East and West bays, inasmuch as it is immediately 

 followed, not by the dark-gray limestones, but by about 200 feet of light-gray limestone; a good 

 deal of which, although it does not weather yellow, is magnesian. The summit of these 200 

 feet is fossUiferous and contains undetermined or undescribed species of Orthis, Ophileta, 

 Maclurea, Nautilus, Amphion, Asaphus, and Leperditia: The 800 feet are probably comprised 

 in the divisions F and G, while the 200 feet may constitute a, part of H. 



The divisions M and N of the Newfoundland rocks have been, in a general way, described 

 from exposures occurring at Table Head. The total thickness was here estimated from meas- 

 urements by pacing, but few details were ascertained; and the fossils collected having been 

 lost, from the necessity of abandoning them on the coast through stress of weather, it was 

 considered expedient to reexamine the locality. The following detailed ascending section is 

 the result. It commences between 600 and 700 feet lower than the strata comprised in the 



