396 FOSSIL SHELL BEDS IN EUROPE. 



and clay, or as what I- have distinguished as true marl. Neither 

 in these very minute descriptions (nor in any others known to me), 

 are shells mentioned as forming either a universal or general con- 

 stituent part of ordinary marls; or as having furnished directly and 

 immediately the main supply of the carbonate of lime of ordinary 

 and true marls. It is true that shells, or their fragments, are men- 

 tioned as being sometimes contained ; but these may be presumed 

 to be accidental ingredients. They are either land shells (and 

 sometimes so described) swept from the surface of the calcareous 

 lands from which the essential materials of the marl were brought 

 in the floods of turbid water; or in other cases, shells of fresh- 

 water molluscs which lived in the ancient lakes under which the 

 marl was deposited, and of course, the shells of such dead animals 

 would be enveloped in the marl, though not necessarily or properly 

 belonging to it. 



Again : " Shell marl" is mentioned by sundry authors, but this 

 is even a more different formation from true marl than it is from 

 our fossil shells. Its peculiar character was stated above (page 

 374). This is the " shell marl" to which Sir John Sinclair refers 

 above. 



If any one can still suppose that these European writers, when 

 speaking of marl, could possibly mean to include such beds as ours, 

 or would so include them, if known there, I have a sufficient answer 

 ready in the fact that such beds of fossil shells as are here called 

 marl exist in Europe and in great extent that they were known 

 to and were described by authors who wrote most extensively on 

 marl and that in no case have they been termed or considered as 

 marl. 



Many and extensive beds of fossil marine shells are known to 

 exist in Europe, which, in their general features, physical and 

 chemical, and fitness for agricultural uses, must be similar to ours. 

 Of these deposits, both in England and France, there have been 

 applications to the land, though to very limited extent compara- 

 tively, and the fertilizing value is recognised. Scientific observers, 

 of course, know that these beds agree with true marl in the im- 

 portant and main characteristic of being in part composed of car- 

 bonate of lime. Still, in the only three agricultural notices of these 

 beds of fossil shells which I have seen, and all are from scientific 

 agriculturists, this substance is not called marl ; and it is noticed 

 under a different head, and treated as if a different manure. The 

 practical cultivators who have applied it, doubtless deemed this 

 manure as different from marl in substance and qualities as in 

 name. 



One of the notices referred to has already been quoted above, 

 (20, page 383), in the words of Arthur Young, concerning the 

 Suffolk " crag" the name used for this deposit in England. This 



