* VOL. XVI.(2) | INFERIOR-OOLITE ECHINOIDS 161 
Cidaris Bouchard: occurs in beds of MWurchtsone and 
Truellez date in the Cotteswolds, in those dated as inter- 
Truellec-zigzag in the Bath-Doulting district, and in post- 
Garantzane deposits in Dorset. No doubt it migrated 
southward into Dorset when connection was established 
between that region and the Cotteswolds. 
Credaris Bouchard: is a “ persistent” species ; for it not 
only occurs at the horizons in the Inferior Oolite already 
mentioned, but it is also found in the Great Oolite ; while 
a closely allied. form—which is very difficult indeed to 
distinguish from it, and which differs only in some minor 
points—occurs in the Bradford Clay, and was named by 
Wright “Crdaris bradfordenszs.” It therefore existed, 
with practically no morphic change, throughout the 
greater part of the “Inferior-” and ‘“ Great-Oolite” 
Epochs. 
Flolectypus depressus, the analogue of Holectypus henits- 
phericus (see p. 162), attains its maximum development 
in the Cotteswolds, where it occurs in beds of about 
Truellet date.{ . is recorded by the officers of the 
Geological Sury , from near Crewkerne, Dorset.’ 
The precise} orizon at which Hydoclypeus gibberulus 
occurs has ng yet been determined, but it is post- 
Garantzane, aq it has been obtained from the Doulting- 
Beds of the nej hbourhood of Doulting, which have been 
dated as part] of Zvwe//ec hemera and partly inter- 
Truellet-zigzag. It has been found near Stroud; at 
Charlecombe, near Bath (by Wright); at Dundry Hill; 
and at Doulting. It also occurs not infrequently in the 
“Top-Beds” of the Inferior Oolite of Dorset. It seems 
to be the last of a series of Galeropygi and Hyboclyper 
which evolved in the Cotteswold area. 
1 “ The Jurassic Rocks of Britain—The Lower Oolitic Rocks of England (Yorkshire 
excepted).” Mem, Geol. Surv., vol. iv. (1894), p, 71. 
