222 Dr H ib bert on the Limestone of Burdiehouse, 



sion, have been frequently lost. Although coprolites contain- 

 ing the indigested scales of fish are most abundantly diffused 

 through the limestone, they seldom preserve any decisive form. 

 An exception to this rule certainly occurs in the argillaceous 

 shale lying above the limestone, indica- 

 tive of a difference of circumstances by 

 which the form of the coprolites has been 

 preserved. This deposit was no doubt ori- 

 ginally a turbid one, calculated to obviate 

 the washing away of any fcecal shape. 

 Two representations of the smaller coprolites are here given. 

 Their form is far better preserved than that of larger specimens. 

 The larger coprolites attain a great size. I have seen them 

 occasionally diffused over a surface of limestone to the extent of 



nearly a foot. 



These fcecal remains are of a pale yellow colour, and have a 

 very dull earthy aspect. In the shale they acquire a darker tint. 



Mr Cornell has undertaken an analysis of these coprolites, 

 which he has accomplished with his usual skill. Two of these I 

 shall subjoin. 



First 

 contains 



Phosphate of Lime, with a little Fluoride of 



Calcium, 85.08 



Carbonate of Lime, 10.78 



Silica, 39 



Potash and Soda, 59 



Bituminous matter, 3.95 



Phosphate of Magnesia, a trace. 

 Animal Matter, a trace. 



Second 

 contains 



83.13 

 15.11 



.29 



1.47 



{ 



with alkaline 

 matter. 



100.79 



100. 



Another analysis of a Burdiehouse coprolite has been recently 

 published by Dr William Gregory and Mr R. Walker ; but 

 as the specimen was unfortunately mixed with foreign matter, 



for instance, with the sulphuret of iron, the result would 



as 



rather mislead. These gentlemen have, however, conducted a 



