Brown: Janassa bituminosa at TJiickley, Durham, 221 



the neighbouring- district has long been famous for the remark- 

 able assemblage of fossils which it contains, especially for ' the 

 number and beauty of the fossil fishes and other vertebrates,'"^ 

 and the locality was noted in the past as one of the best collect- 

 ing grounds for British Permian vertebrata. Owing to the 

 quarry becoming disused in the 'seventies,' no collecting has 

 been done here since then. Quite recently, however, another 

 portion of the quarry has been opened, the Coal Measure 

 sandstone being worked as a building material. A careful 

 examination of the Marl Slate overlying this has resulted in the 

 discovery of a few fossil fish for which the Marl Slate is so well 

 known, specimens belonging to the genera Palceoniscus , 

 Acentrophoriis^ PLatysomiis , Acrolepis , and Pygopteriis having 

 been found ; although the fossils are very scarce, somewhat 

 fragmental, and not present in this portion of the Marl Slate to 

 anything like the extent in which they were obtained in other 

 parts of the quarry by Duff, Howse, Calvert, and other 

 collectors long ago. 



One specimen of the teeth of Janassa hitiiminosa has been 

 obtained, a drawing of which is shown (Plate XVIII., Fig. 2). 

 The remains of this fish are of very rare occurrence in the British 

 Marl Slate, but are fairly common in the German Kupferschiefer, 

 the division of the German Permian corresponding to our Marl 

 Slate. Schlotheim first named the fish and showed its relation- 

 ship to the Petalodontidae, a family of the Batoidei or Ra3\s. 



During the years 1865-1869 the late Joseph Duff, of Bishop 

 Auckland, found four specimens of the teeth of this fish in the 

 Marl Slate of Middridge, which is quite close to the place 

 where the present specimen was obtained. Hancock and Howse 

 described these t, and stated then that they were the first and 

 only specimens discovered in England ; they gave the following 

 general description of the dental armature of this fish : — ' The 

 teeth are arranged in both upper and lower jaws ; in both they 

 are placed in transvere horizontal rows (there being from four 

 to seven such rows) across the anterior portion of the jaws. 

 Each such horizontal row is composed of seven teeth (five 

 primary and two secondary), placed lengthwise with the cutting 

 edge in front. A large symmetrical primary tooth is situated 

 in the centre ; on each side of this there are a first and second 

 asymmetrical primary tooth, making up the five primaries. These 



*' Geolog-y of Northumberland and Durham.' by Prof. G. A. Lebour, p. 35. 



t' Transactions of the Natural History Sociei}' of Northumberland and 

 Durham,' 1874. 

 1905 July 1. 



