Geological Society of London. 105 
Species in which a change hasbeen proved diminishes as we 
ascend in time. Among other points, M. Barrande has made 
out the probable eggs of these animals. As to their mode of 
life, he opposes the conclusion of Burmeister and others, that 
Trilobites lived in shallow water along the coast; and dis- 
tinctly pronounces against the supposition of their parasitic 
nature. 
A great step has been made towards an explanation of 
some of the organic phenomena of the Oolites by Professor 
Morris, whose memoir “ On some Sections in the Oolitic 
District of Lincolnshire,’ communicated to the Society in 
June last year, throws new and valuable light on the rela- 
tions of the southern to the northern oolites in England, and 
rectifies several misconceptions about the comparative order 
of the strata in different districts. As this paper, one of the 
most important in its general bearings laid before us during 
the past year, is printed entire in our Journal, I shall make 
no abstract of its details, but merely offer a few remarks on 
its general bearings. 
The marine faunas of the Oolitic epoch indicate at least 
three great and widely-spread assemblages of types, each 
exhibiting a general and easily recognizable facies. These 
aspects may be termed respectively the Liassic, the Batho- 
nian, and the Oxfordian ; the two latter terms being used 
for want of better, and being adopted in a wide and general 
sense, and not in the restricted meaning in which they are 
used by M. Alcide d’Orbigny. The horizon of change of 
facies at the boundary between each is a horizon, to a con- 
siderable extent, of change of species. I believe that every 
year’s research will make it more and more evident that the 
perishing of species is simply the result of the influence of 
physical changes in specific areas, and depends upon no law 
of inherent limitation of power to exist in time. If so, we 
should expect to find indications of the cause of the greater 
changes in the oolitic and marine fauna in the shape of strata 
bearing evidence of a wide-spread change of physical condi- 
| tions within the great oolitic area. An extensive change of 
Species within a marine area, in all likelihood, is dependent on 
an extensive conversion of that area into a terrestial surface. 
