468 PEOCEEDINGS OP THE GEOLOGICAL SOCIETY. [May 9, 



and filled up with marine or fluviatile gravel, and reexcavated prior 

 to the epoch of the high- and low -level valley-gravels. 



2nd. That all these gravels are reconstructed of drift and gravel 

 of the Glacial period, or of its equivalent south of the Thames, mixed 

 with a certain amount of local materials. 



3rd. That the high- and low-level gravels are of one formation, 

 closely connected in age, and dating from a time immediately pre- 

 ceding the historical period. 



May 9, 1866. 

 The following communications were read : — 



1. On a N'ew Species of Acanthodes from the Coal-shales of 

 LoNGTOi^. By Sir Philip de M. Grey Egeeton, Bart., M.P., 

 E.R.S., E.G.S., &c. 



[Plate XXIII.] 



Owing to the kindness of Mr. Ward, of Longton (who has for some 

 time past devoted his time and attention to collecting the fossil 

 remains of the coal-pits in his vicinity), I have had the opportunity 

 of examining a considerable collection of specimens of the Acantho- 

 dian fishes of the North Staffordshire Coal-measures. Numerically 

 speaking, the collection is a large one, but the specimens themselves 

 are all imperfect. The anterior parts of the fish are rarely pre- 

 served ; and even when present, the dislocations and crushed condition 

 of the component bones are so extensive that the form and structural 

 details of the head and thorax are difiicult to decipher. Most of the 

 best-preserved specimens contain the middle and hinder portions of 

 the body, from the ventral. spines to the bifurcation of the tail; and 

 all have the scales well shown, and most of the spines supporting 

 the fins. Although it might perhaps be desirable to wait for more 

 perfect specimens before undertaking a complete determination of 

 the specific forms, yet the evidence already procured is so decisive 

 as to the distinctness of at least one species, that a brief description 

 of this form may be given without prejudice to future investigation. 



The generic characters of Acanihodes have been so thoroughly 

 worked out in previous publications * that it is needless to recapitu- 

 late them here, the more so since no important anatomical points 

 are supplemented by the specimens under consideration. 



Selecting for description those individuals of a medium size, the 

 length of the body, from the snout to the point where the vertebral axis 

 trends upwards to form the upper lobe of the tail, seems to have been 

 about 5^ inches. Of this total the anterior third comprises from 

 the nose to the point of insertion of the ventral spines, the middle 

 third from the ventral spine to the anal spines, and the posterior 

 third from the anal spine to the point above mentioned. Estimating 



* Agass. Poiss. vol. ii. p. 9. Herr Fred. Eomer, Ueber Acanthodes gracilis : 

 Breslau, 1857. Memoirs of Geological Survey, Decade 10. pp. 37 & 57. 



