178 Dr Hibbert on the Limestone of Burdiehouse, 



ultimately referred to the Spbenopteris bifida, any farther notice of it will 

 be suspended. 



Fig. 3. is the Sphenopteris linearis. 



Fig. 4. is the Sphenopteris affinis. In this sketch the Rachis is rather too slen- 

 derly drawn. 



Fig. 5. is the Lepidophyllum, in connection with Cyperitis bicarinata. 



Fig. 6. shews the Lepidostrobus variabilis enclosed in the same specimen with a 

 fish of the genus of Palaeoniscus, which will be described in the 7th sec- 

 tion of the present memoir. 



SECTION IV. -THE MICROSCOPIC ANIMALS CONTAINED IN THE LIMESTONE 



OF BURDIEHOUSE. 



No conchifera, at least of any large size, have hitherto been 

 discovered in the limestone of Burdiehouse. 



From having witnessed the great abundance in which fresh 

 water unios are contained within a thin band of limestone and 

 shale, near Old Cumnock, in Ayrshire, and from having read in 

 Mr Ure's History of Rutherglen, that they had been found un- 

 der similar circumstances near Glasgow, I had long anticipated 

 their discovery in the fresh-water limestone of Burdiehouse. But, 

 if not found in the bed itself, they at least exist in a superincum- 

 bent bed of argillaceous shale which encloses similar organic re- 

 mains. 



The animals actually found in the limestone of Burdiehouse 

 merit a particular regard : For there are assuredly no phenomena 

 connected with the deposit of Burdiehouse more remarkable 

 than the Entomostraca with which it abounds. 



These minute animals are severally microscopic, ranging from 

 T Vth to ^Vth p ar t of an inch. Various kinds are found among 

 them, all of which, with perhaps the exception of one genus, ap- 

 pear to have been perfectly undescribed. Nor is it the easiest of 

 tasks to submit them to any kind of successful investigation. 

 We see nothing more in these crustaceous animals than their 

 outer and shelly case, while a mineralized state has obscured their 

 internal organization. Accordingly, if we conceive that cer- 

 tain minute oval bodies resemble recent specimens of the Cypris 



