88 . GENESIS OF THE ARIETIDA. 
ments to the north, to which Waagen adds Dorsetshire and Wiltshire in southern 
England. VI. North English Basin, from Gloucestershire to Yorkshire inclusive. 
VII. North German Basin, including Hanover, Brunswick, and the neighbor- 
hood of Magdeburg. 
We have not needed to use these divisions precisely as laid down by Waagen, 
but it is interesting to remark that they accord more or less completely with the 
observations on the faunas here recorded. Our principal interest has been, of 
course, in the central portion of each basin, and not in the more deficient records 
of outlying localities. The South German basin is as it has been given by 
Waagen. His Helvetic basin appears to be a natural division, with the exception 
of the departments of Saone et Loire, the Cote d’Or, and the Rhone. The Cote 
d@’Or has appeared to us to be the centre of a different basin, which extended in- 
definitely through the departments to the westward, and also to the south until 
it met the fauna in the valley of the Rhone described by Dumortier. Whether 
such closely contiguous faunas as that of this valley and the Cote d’Or ought to 
be designated by distinct names we cannot pretend to decide, but that they differ 
materially from the point of view of the evolution of their faunas seems to us 
highly probable. 
The faunas of northeastern France and Luxemburg, though perhaps in a dis- 
tinct basin from those of Westphalia, Hanover, etc., which are properly included 
in the North German Basin, are all similar in so far as they contain similar resid- 
ual faunas. The basin of the Rhone includes the departments mentioned as in 
the Mediterranean basin by Waagen, with the exclusion of the southeastern part 
of the department of Var, which, as shown by Dieulefait, belongs to the Italian 
basin. We have not been able to study any collections from Wiltshire, but the 
Dorsetshire fossils of the Lower Lias, though certainly presenting a very distinct 
facies and association of forms from those of Waagen’s North English basin, have 
not seemed to require separation into a different basin. The fossils do not resem- 
ble those of any other fauna so closely as they do that of the rocks in the rest 
of England to the northeast, and, though it may be natural to make this separa- 
tion, we have not required it for the immediate purposes of this memoir, and have 
consequently spoken of the entire region as the English basin. 
The Lias in territories to the north, like Scotland and Sweden, is deficient in 
Ammonitine, and Judd! remarks upon the estuarine character of the deposits. 
At Dompau and Dishult in northwestern Sweden a few poorly preserved fossils 
show the presence of the bucklandian fauna. It is possible that these deposits 
may have a yet undiscovered fauna of Ammonitine distinct from more southern 
localities ; but so far as one can see, the forms of the Swedish basin are not dis- 
tinct from those of the faunas of North Germany. 
Neumayr has already traced in a general way the origin of the fauna of 
Central Europe to the Mediterranean province, and we think a still further 
advance has been made practicable by the methods of constructing genetic series 
as advocated in this monograph, and the discovery of definable cycles in the 
genesis of forms. Though our conclusions have been reached under the dis- 
1 Quart. Journ. Geol. Soc. London, 1873, XXIX. p. 98. 
