118 FOSSIL ESTHERIJE. 



being angular, and the opposite one rounded. I have some nearly a quarter of an inch 

 across. At first I imagined that these were scales of fish, but now think they must be 

 some bivalvular shell. Their surface is marked with strong concentric ridges ; and passing 

 from the hinge (?) to the opposite corners are two diverging elevated lines. I cannot 

 detect any traces of teeth ; but have found several specimens in which the two valves (?) 

 were connected at the hinge, and the four ridges commencing from one common point in 

 the centre, and diverging two each way ; these I pointed out to Prof. Phillips, who will, 

 perhaps, be able to lay before the public some more decided opinion as to their nature ^" 

 (p. 351). 



At page 245 of the same paper, Prof. Williamson gave a section of the strata at 

 Ardwick, which will serve to illustrate the exact position in which these curious little fossils 

 were found. The section^ is as follows : — the fossils mentioned in the paper as peculiar to 

 the beds being inserted in their places. 



Feet. Inches. 

 Red clays with sandstone (Unio Phillipsii^ in one thin seam), thickness not 



known. 

 Limestone. " Four-feet Mine." (Megalichthys Sibherti m i\\QXQO^. Microcon- 



chus.) 4 



Red and blue clay. "Clunch." 6 



Coarse micaceous grit .....' 6 



Clunch 6 



"Roof-stone;" a sbaly sandstone 3 



Limestone. "Yard Mine." {Microconchus.) 3 



Clunch 5 



Limestone (fragmentary shells in the upper portion : Unio 1) 2 



Clunch and shaly clay 17 



Limestone 1 



Red shale. {Asterophyllites, Calamites decoratus, O. nodosus, Lepidodendron 



Sternbergii, Stigmaria ficoides, Newopteris cordata, Cydopteris, 



Pecopteris) 15 



Limestone 1 6 



Coloured clays 45 



Blue clay. {Entomostraca \_Leaid], Unio Fhillipsii, Sphenophjllum, Pecopteris, 



Uquisetum.) : 1 



"Black bass:" pyritous shale. {Unio Phillipsii, CypridcB, Vish-remains.)... I 



Coal. (Slifftnariajicoides.) 6 



1 Professor Phillips referred to these little fossils in the 'Silurian System,' p. 89 (1839) and sug- 

 gested that they may be Jptychi {Trigonellites) . 



2 The place of these strata in the general section of the Manchester district is shown in Mr. Binney's 

 paper, 'Trans, Manchester Geol. See.,' vol. i, p. 50, pi. 1, fig. 1. 



3 Prof. Phillips terras this shell U. linguiformis {' Sil. Syst.,' p. 88) ; Mr. Binney thinks it may be a 

 Modiola ('Manchester Lit. Phil. Soc. Mem.,' vol. xii, p. 221); and Mr. Salter regards it as an 

 Anthracomya. 



