1382 
J. Love—Comparative Fertility of Soils. 
Idmonea cytherea, d’Orbigny, 1853: loc. cit., pl. 750, 
figs. 11-15 ... R. carinata. 
26. Crisina ramosa, @’Orbigny, 1851: loc. cit, Ph 611, 
figs. 11-15 i ... &. ramosa. 
Idmoneu macilenta, von Hagenow, ‘1851: Bry. “Maastr. 
kr., pl. ii, fig. 4 a 
Tdmonea divaricata, aU 1865, Bry. Schicht. Maastr. : 
Verh. naturh. Ver. Preuss. Rheinl., vol. xxii, pl. i, 
fig. 8 oe iss ad a 
27. pee clathr cat, Goldfuss, 1827: loc. cit., pl. x, figs. 4 
12¢, d R. clathrata. 
28. 
Tdmonea clathr ata, von 1 Hagenow, 1851: Bry. Maastr. kr., e 
pl. u, fig. 2 : 
Retecava ‘elathrata, qd’ Orbigny, 1853: pl. 790, figs. 5-9. 
Idmonea verriculata, von Hagenow, 1851: Bry. Maastr. 
ky., pl. ii, fig. 5 . 
Idmonea carinata, Roemer, 1840: loc. cit., pl. v, fig. 20. 
97 
R. carinata. 
29. Idmonea filiformis, d’Orbigny, 1853: loc. cit., pl. 750, 
figs. 1-5 . ah ee ... LR. pseudodisticha. 
Tdinonea angulosa, a Orbigny, 1853: loc. cit., pl. 748, 
figs. 11-15 F ae s ... C. angulosa. 
Tdmonea man ‘ginata, a’ Orbigny, 1853: loc. cit., pl. 749, 
figs. 20-23 C. marginata. 
38. 
Idmonea lata, d’ Orbigny, 1853 : loc. cit. pl. 748, figs. 6-10. 
figs. 94-96 ; 
Clavitubigera convexa, a Orbigny, 1853: loc. cit. , pl. 746, 
figs. 12-15 
Clavitubigera cngustata d’ Orbigny, 1853 : loc. cit. , pl. 746, 
figs. 16-20 
Clavitubigera excavata, @’ Orbigny, 1853: loc. cit. pl. 747, 
figs. 6— 
Idmonea Fischer, Pergens, 1890 : loc. cit., pl. xii, fig. 4. 
GroLocgicaL ForMATIONS. 
By Jamus Love, F.G.S., F.R.A.S. 
99 
Idmonea excavata, d’Orbigny, 1853: ‘loc. cit., pl. 749, 
figs. 11-15 poe 200 380 99 
Idmonea calypso, @ Orbigny, 1853: loc. cit., pl. 747, 
figs. 11-14 oie on ... @. cenomana. 
30. Idmonea plana, Pocta, 1892: loc. cit., pl. ii, figs. 1,2 ... C. plana. 
381. Claritubigera navicularis, Beissel, 1865: loc. cit., pl. vii, 
C. navicularis. 
C. convexa. 
9 e = 
C. Fischeri. 
9 
VII.—Tae Comparative Frertiniry oF THE SOIL ABOVE CERTAIN 
HILE travelling over the country it may be noticed that the land 
is not uniformly fertile. 
In some places there is greater 
luxuriance and greater variety of plant life than in others. 
The 
question which such observations call forth is what is the cause of © 
these differences? An attempt has been made to give some sort 
of answer to this question in the following manner :—A limited area 
has been selected which is traversed by a number of geological 
formations, and the plants growing on that area have been catalogued. 
The area selected in the present instance is the county of Surrey, that 
being the county which is best known to me. Surrey is too small 
a county to have any difference of climate. The differences of altitude 
would probably bring about some variety in the flora, but the differ- 
ences of latitude could scarcely have any appreciable effect. The 
county is, however, large enough to include a dozen different rock 
