400 Walker — Greensand Brachiopoda, 



The coprolitic bed becomes more indurated towards the bottom : 

 the last two or three inches, being very difficult to pierce, are gene- 

 rally left. The coprolites towards the bottom of the bed are 

 darker in colour. The coprolitic bed only extends partly across the 

 field, the Coralline Oolite abruptly terminating the trenches which 

 are dug in working the deposit.* 



I regard the following as new species : — 



Waldheimia midabilis, sp. n. PL XIX. Figs 4 and 5. — The 

 specimens to which I refer under this specific name, present two 

 strongly marked varieties or sub-species ; indeed the differences 

 between these forms are so striking, that I was at first inclined to 

 regard them as constituting two species, until the discovery of inter- 

 mediate forms convinced me that, notwithstanding the remarkable 

 discrepancy in their aspect, they were to be regarded as one : 

 I have, however, considered it desirable to give names to the two 

 forms. 



W. mutaUlis. — Shell-surface smooth, very slightly marked by 

 faint lines of growth. Beak short, nearly straight, truncated by a 

 small triangular foramen; beak ridges moderately well defined, 

 space between the ridges and hinge-line nearly flat ; deltidium large, 

 in two pieces ; loop long, front margin not plicated or waved. 



Var. or sub-sp. W. elUptica. PL XIX. Fig. 4, 4a-4J. Shell 

 ovate, its edges sharp, both valves are nearly flat but slightly convex 

 towards the beak. Dimensions: length, 1-375 inches; breadth, 1*125 

 inches ; thickness, '625 inches. 



Var. or sub-sp. W. angusta. PL XIX. Fig. 5-6a. Shell very 

 much elongated, very narrow compared with its length, both valves 

 moderately convex. Dimensions : length, 1*42 inches; breadth, 

 •75 inches; thickness, -42 inches. The var. W. elliptica approaches 

 nearest to some forms of T. depressa, from which it can be readily 

 distinguished by the loop, by the smaller size and triangular form 

 of the foramen, and by the deltidium being in two pieces. The var. 

 W. angusta is well distinguished from W. celtica by its nearly 

 straight beak, and by being narrower, etc. From T. extensa by its 

 loop, etc. 



Waldheimia rliomhoidea, sp. n. PL XVIII. Figs. 3, 3a., 36. and 4. 

 — Shell elongate, widest near the middle of the shell, thence gra- 

 dually narrowing towards both extremities, so as to acquire a some- 

 what rhomboidal form. Beak incurved, truncated by a moderate- 

 sized foramen. Beak ridges sharp, space between the ridges and 

 hinge-line concave ; deltidium in two pieces. Shell surface smooth, 

 marked by faint concentric lines of growth. Both valves regularly 

 convex, frontal margin not plicated, loop long. Dimensions : length 

 •94 inches to '625 inches ; breadth '625 inches to '5 inches ; 

 thickness, -5 inches to "375 inches. This species approaches nearest 

 to W. Morrisii Meyer and W. tamarindus, Sow. It may be dis- 

 tinguished from W. Morrisii by its peculiar elongated form tapering 



^ Sec notice by Mr. Henry Keeping (the intelligent assistant to Prof. Sedgwick in 

 the AVoodwardian Museum) in the Geological Magazine for June last (p. 272) 

 of the succession of beds in the Upware deposit, accompanied by a woodcut. 



