152 Dr Paterson on the Fos&il Organic Remains 



occur, is also abundantly charged with ferns and other plants of the coal for- 

 mation, and with the crustaceous remains of cvpris, a genus known only as an 

 inhabitant of fresh water. 



" These circumstances and the absence of corals and encrinites, and of all 

 species of marine shells, render it probable that this deposit was formed in 

 a fresh-water lake or estuary; it has been recognised in various and distant 

 places, at the bottom of the carboniferous strata near Edinburgh." 



But while some individuals seem thus to adopt the opinion of 

 Dr Hibbert, there are not a few who have been all along satis- 

 fied that the limestone of Burdiehouse was no other than the 

 common one of the coal formation. This opinion was formed 

 not from any contradictory evidence with regard to fossils, but 

 chiefly from the geological relations of that rock to the coal 

 series in the immediate neighbourhood. 



These microscopic crustaceous remains occur at Wardie, 

 chiefly in the slate, and are to be seen in conjunction with a 

 small shell of the genus Ostrea, with corallines, with plants to 

 be referred to the genus Fucoides, as well as with the multitude 

 of terrestrial plants. 



Dr Hibbert's arguments are chiefly based on the vast 

 abundance of these microscopic Entomostraca, together with 

 the absence of marine remains ; but certainly these assumptions 

 do not aflPord sufficient grounds for asserting, that the deposition 

 took place in a fresh-water lake. 



The occurrence of fresh-water strata alternately with marine 

 in the common coal-fields, has long been known, and was attri- 

 buted to the varying relative abundance of fresh or salt water : 

 some of these fresh-water strata might have been of consider- 

 able thickness, and yet few would have supposed them to have 

 been lacustrine. The strata in this place, however, distinctly 

 shew the unsatisfactory nature of the arguments which have 

 been brought forward to prove the lacustrine origin of the Bur- 

 diehouse and other limestones in this neighbourhood, because 

 they contain microscopic entomostraca in conjunction with co- 

 rallines and shells of the genus Ostrea, as well as with abundance 

 of terrestrial plants, and genera of fish similar to those of the 

 supposed lacustrine formations. From these facts it is evident 

 that the strata here have been deposited in an estuary. 



The fishes which have been noticed here mav all be referred 



