Vol. XXviii.] PALEONTOLOGY OF LANCASHIRE COAL MEASURES. 581 



various private and public museums in the county, and 

 finally I have checked my results by an examination of the 

 whole of the Transactions of the Society from the first 

 volume onwards, and of the Geological Survey Memoirs. 

 As far as possible, with all the species, localities, and 

 horizons mentioned, I have added the name of my authority, 

 or given a reference to the whereabouts of the specimen, and 

 the collection of which it forms a part. 



It will be noted that not merely have I recorded known 

 species but also the occurrence of specimens, the species of 

 which have not been determined. 



This has been done either because I could not determine 

 the specific identity of the fragments, whilst there was no 

 doubt of the genus, or that I have quoted some authority 

 who did not give the species. 



Even without specific identity, the records of these 

 specimens are useful, inasmuch as they indicate the occur- 

 rence of certain genera at certain definite horizons. In the 

 present state of our knowledge these unknown species 

 represent determinative work yet to be done. Further 

 research on these horizons, and at these localities, may 

 perhaps prove that no further species have to be added to 

 the list here given, but it is far more likely that other 

 species besides those recorded in this paper will reward the 

 diligent student. The observations made by Mr. George 

 Wild in the Transactions of this Society, Yol. XYII., 

 p. 225, on the nature of the measures in which fossils occur, 

 scarcely needs any addition. Speaking generally, animal 

 fossils are most abundant in the black shales, and less so in 

 the blue shales. The black shales most frequently lie upon 

 the coal seams, often forming the roof, and there seems no 

 question in regard to the Middle Coal Measures at any rate, 

 but that the majority of the animal fossils do occur in close 

 relation to the seams. Between a typical black shale, and an 



