230 



The thin brown shales, No. 19, which measure 18 inches, contain only 

 the scattered scales and remains of Fish over their several laminae, and 

 serve to distinguish and separate the Modiola minima bed. No. 20, from 

 those immediately below. This xipj^ermost bed in the Rhsetic series 

 at Westbury Cliff is a dull pale brown or grey hard Limestone, 

 with Modiola minima and Ostrea liassica abundantly distributed 

 through it. So closely allied to the Lias in character is this Limestone, 

 that it requires us only to find an Ammonite to determine it to be of 

 Lias age.* 



The generalizations deducible from the foregoing brief description of 

 the strata and organic remains and their conditions at Garden Cliff are 

 numei'ous and important, more so perhaps than we are at first disposed 

 to believe; and it is obvious, from the amount of interest which these 

 Rhsetic beds and the whole subject has of late created, that much 

 diversity of opinion will and must exist with relation to the true history 

 of these beds in time, especially when we consider that we have not 

 perhaps in England, in one section, a complete sequence of the whole sei-ies, 

 both as regards the life or organic contents, or the physical conditions 

 by which to estimate or coi-relate with continental sections: — but the 

 physical condition we cannot expect to obtain, owing to the varied jjhe- 

 nomena attending deposition of sedimentary matter over large portions of 

 the earth's surface, and which diversity must necessarily occur, and operate 

 to prevent a uniform condition of things over wide spread yet continuous 

 and connected areas. On the other hand we may, however, \inderstaud, 

 through strict research and patient analysis, the life succession, and 

 distribution of the sjjecies in time, constituting the fauna of this gi'oup of 

 remarkable rocks. For it is certain that in England, with few exceptions, 

 we possess most of the forms kno^vn to occur in beds of this age in 

 Europe, thus clearly defining that the Rhsetic species, as regards their 

 distiibution in space, had a very wide range, and at the same time 

 demanding from us extended notions of time for the dissemination or 

 distribution of the species over a large portion of Europe, and perhajjs 

 Asia; and looking at the cosmopolitan distribution of such forms as 

 Avicula contorta, Fecten Valoniensis, Cardiuni lihceticum, Pullastra 

 arenicola, &c., and their ubiquitous condition, or vast abundance indi- 

 vidually in the rocks, both in our own country and Europe, and their 

 definite arrangements in zones almost illustrating epochs, demand and 



* A most remarkable zone in the Patchv/ay district, its upper part being highly 

 fossiliferous ; Pholodomya glabra, Unicardium, Ostrea liassica, Modiola minima, 

 Lima, a Cardium (nov. sp.) all occurring in great abundance. 



