80 SUPPLEMENT TO GREAT OOLITE MOLLUSCA. 
dimensions, with a lengthened general form, compressed anterior side, and large longitudinal 
plications over the whole of the surface; it appears to be comparatively rare, and belongs 
to the upper stage of the Inferior Oolite. 
Turacta AMYGDALOIDEA, Lyc. Tab. XLIII, fig. 4. 
Testa convera, elongata, umbonibus depressis submedianis, latere antico producto, ro- 
tundato ; postico subcompresso, attenuato, basi curvato, plicis longitudinalibus paucis, 
leviter tnstructis. 
Shell elongated, convex ; umbones postero-mesial, depressed ; anterior side produced, 
its margin curved elliptically ; posterior side rather compressed and attenuated, its superior 
border slightly excavated; the base is uearly straight; the surface has a few faintly 
marked, longitudinal plications of growth. 
Compared with other examples of the genus, the length and the convexity are con- 
siderable ; the umbones are likewise much depressed, obtuse, and but little conspicuous ; 
the posterior angle is only distinguishable near to the umbones ; the posterior extremity is 
slightly truncated. The height only very slight exceeds half the length. 
Geological Position and Locality. Associated with valves of A/yacites calceiformis in 
flagey, argillaceous Oolite, upon the western border of Minchinhampton Common, at the 
lower boundary line of the Great Oolite ; a single specimen. 
Myactires caucrrrormis, Pdi/., sp. Part II, Tab. XI, fig. 2; et Tab. XLII, figs. 1, 1 a. 
As this shell possesses considerable variability of figure, another example is given from 
the Cornbrash of the Yorkshire Coast. In the former description (p. 114, line 8), these 
words should be erased —‘ iz the upper beds of the Inferior Oolite.”’ An examination of 
numerous Yorkshire specimens has proved that they were all obtained in the Cornbrash, 
including the original specimen figured in the ‘ Geology of Yorkshire,’ which was erroneously 
placed with the Inferior Oolite fossils, and figured with them in pl. xi of that work. 
The Cornbrash specimens have the test with its granulated tegument well preserved, but 
usually the fossil has undergone some compression or distortion. The former figure, 
Plate XI, fig. 2, represented a Minchinhampton specimen from the base of the Great 
Oolite. An Inferior Oolite shell frequently mistaken for J/yacites calceiformis occurs 
only in the form of casts; it is more gibbose, with larger, more elevated umbones, the 
posterior side being much shorter and more attenuated. As the casts are common, and 
these distinctive characters are persistent, there can be no doubt that it must be dis- 
tinguished from the species of Professor Phillips. Authorities generally have followed the 
‘Geology of Yorkshire,’ and placed J/yacites calceiformis in the Inferior Oolite, and Dr. 
