172 REPORT—1843. 
Conchological Table, No. II. 
Distribution of Celtic forms in the several zones. 












| oy fu. | om liv. |} v. | ove va. lve. 
Multivalvesous: <. celteoun ] Gris 1 ] 1 ] 0 
Patelliform univalves...... 0 1 Li ae dol pelle Ba aga al Ppl 
Tubular univalves ........ 1 1 Or eO sO.) 20a Onteaae 
Holostomatous spiral uni- | 
“cl | vinta pe thet a5 <0 30 12) 9118/16/14] 11] 81 4 
Siphonostomatous spiral uni- 
valves ...... I lg wi: Sh Mi haw i bas iI Ph 2 Menard le 
Testaceous Pteropoda, and 
Nucleobranchia ........ nem erate ari dh seca! CK 0; 0 
Brachiopod a. qa5tes 90° Seay rie Of Oro.” OC tam 
ConchiferaLamellibranchiatal 16 | 25 | 28 | 39 | 33 | 19 | 11 vi 
24} 41 | 50 | 66} 57 | 39 | 27 | 18 
II Il \| ll Il} Ul | Al 
peed aE fe OL RR aR 
solo lwvlulswis isis 
oO is) iq?) oO oO oO ie] oO 
bal a) Lar J bar | be | be] ar] Le | 
° oO ° ° a ° Q ie) 
@ o oO ie) (> oD Oo oO 
seleptsiebilgeshs ]s 1s 
ee pose | ge PopR | FR T ses gee 

The importance of these results must be obvious to the geologist, The 
inductions as to climate or distribution which he may draw from his exami- 
tion of the Testacea of a given stratum, will vary according to the depth in 
which those Testacea lived and the ground on which they lived ; for every 
zone of depth yields a different percentage ; and as the nature of the ground 
determines the tribe of Testacea which frequents it, and as every tribe yields 
a different per-centage, according to the variation of character of the sea-bot- 
tom, so will the conclusions of the geologist vary and become uncertain. The 
remedy is however obvious. By carefully observing the mineral character of 
the stratum in order to ascertain the nature of the former sea-bottom, by 
noticing the associations of species and the relative abundance of the in- 
dividuals of each in order to ascertain the depth, and by calculating the per- 
centage of northern or southern forms separately for each tribe, our conclu- 
sions will doubtless approximate very nearly to the truth. 
A comparison of the Testacea and other animals of the lowest zones with 
those of the higher exhibits a very great distinction in the hues of the species, 
those of the depths being for the most part white or colourless, whilst those 
of the higher regions, in a great number of instances, exhibit brilliant combi- 
nations of colour. The results of an inquiry into this subject are as follows : 
The majority of shells of the lowest zone are white or transparent : if tinted, 
rose is the hue; a very few exhibit markings of any other colour. In the 
seventh region white species are also very abundant, though by no means 
forming a proportion so great as in the eighth. Brownish-red, the prevalent 
hue of the Brachiopoda, also gives a character of colour to the fauna of this 
zone: the Crustacea found in it are red. In the sixth zone the colours 
become brighter, reds and yellows prevailing, generally, however, uniformly 
colouring the shell. In the fifth region many species are banded or clouded 
