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ordinary littoral conditions — fringing as they do, upturned 

 Cambrian and granitic rocks, we must therefore omit the con- 

 tents of these recifs as they are named, from our consideration ; 

 they afford us little light and scant support, stratigraphically. So 

 that such continental authors, must continue to designate this 

 portion of the lias by the name of Amaltheenthone or Upper 

 Margaritatus Beds or Zone of Peden cequivalvis, or as in Cernes, 

 the Marnes a plicatules. In this state of the subject, we may 

 well inquire what is the significance and testimony of our North 

 Gloucestershire beds in their bearing upon the question. A 

 thorough and patient examination of them brings out the fact 

 that they directly support the view which postiilates the 

 existence of a Spinatus Zone. Our Churchdown Sands were no 

 doubt laid without interruption within the protection of a quiet 

 coast line, and this advantage connected with the fine character 

 of the filmy marly sediment conduced to render them well 

 adapted to receive and transmit to us the representative forms 

 of life of that liassic epoch. The testimony then of this portion 

 of the Cotteswolds hills and outliers, is when carefully 

 interpreted unassailable. This witness is mainly from the 

 palseontological side of the question. Moreover, the difference 

 between the petrology of the Spinatus Zone and the Margaritatus 

 Beds is of a marked character. We are, therefore, fully justified 

 in concluding that the Middle Lias of the Cotteswold for North 

 Gloucestershire in regard both of its fauna or assemblage of life, 

 and its petrology, is in favour of such a subdivision as the Spinatus 

 Zone, which now we will proceed to examine more closely. 



II. SYNONYMS OF THE SPINATUS ZONE. 



We would usher in our list of some of the chief names that 

 have been given to the Spinatus Zone, by directing attention to 

 a distinction in the application of the word Synonym. When 

 applied to fossils, these countless designations, though un- 

 fortunately a necessary evil, are a hindrance rather than a help. 

 But when applied to groups of strata homotaxially, situated, a 

 list of the chief synonyms judiciously selected from the best 

 authorities, gives when read aright, the following clue : — 



