344 SKY. GEOLOGY. SECONDARY STRATA. 



by the name of double-headed shot; a peculiarity that 

 has been noticed by foreign geologists. 



The limestone presents various tints, varying from 

 dark lead colour to smoke grey, and in some places 

 it becomes of a dead greyish white. It is frequently 

 so charged with argillaceous and siliceous earth as 

 nearly to lose its character; in which cases it refuses 

 to burn and scarcely effervesces with acids. The beds 

 vary in thickness, but are generally thin, and divided 

 by laminae of schistose clay and by an impure argil- 

 laceous brown sandstone. I may remark that the only 

 beach along the greater part of this shore consists of 

 these flat beds, stretching out to a certain distance 

 from the foot of the cliffs so as to be covered at high 

 water mark, but accessible at low water; at which time 

 alone it is possible to examine the rocks in a satisfactory 

 manner. 



The only organic remains which I observed in these 

 rocks are a belemnite and two or three ammonites, and 

 they occur both in the limestone and in the accompanying 

 strata. The former is of a large size, varying from 

 nine to fifteen inches in length, and is sometimes so 

 perfect as to contain the interior septa of the shell. 

 One of the ammonitge is also of considerable size, 

 varying from a foot to eighteen inches in diameter, 

 and exactly resembling that found in Rasay. A second 

 is of a smaller size, forming a distinct species, and both 

 of these bear a considerable resemblance to the smaller 

 species of this genus found in Somersetshire among the 

 lias beds. A third, of large size, forms a species apparently 

 new to conchologists, since the spiral terminates in a 

 peculiar manner before it meets the centre, leaving an 

 open ring in the middle, of two or three inches in dia- 

 meter. I may add that the belemnites are abundant, 

 but that the ammonites are rare ; nor did I, on this part 

 of the shore, discover any other species; the gryphites, 



