used for Agricultural Purposes. 
401 
lites appear generally as dark grey or greenish-black coloured 
hard nodules ; some are small, and most of them are larger in 
size than Cambridge coprolites. The percentage of phosphate 
of lime in Boulogne coprolites seldom exceeds 4G per cent. ; it 
frequently falls below 45, and even to 40 per cent, and less, 
if the raised coprolites are not well washed and thoroughly dry 
before shipment. 
During the last year or two I have made a large number of 
analyses of French coprolites, from which I select the following 
complete ones : — 
Detailed Composition of Boulogne Coprolites. 
No. 1. 
No. 2. 
No. 3. 
No. 4. 
No. 5. 
84 
79 
1 
OS 
1-18 
1 
74 
Water of combination and loss\ 
3 
14 
3 
24 
3 
08 
1-91 
1 
04 
21 
OG 
21 
27 
21 
27 
20-70 
17 
69 
33 
06 
35 
38 
33 
68 
30-41 
31 
12 
3 
55 
5 
25 
4 
52 
3-94 
5 
13 
6 
81 
{ . 
89 
??} 
3-24 
85 
Fluorine, aud loss in analysis / 
08 
2 
{ . 
96 
58 
25 
69 
•83 
56 
2 
89 
3 
63 
3 
54 
6-24 
3 
52 
3 
09 
3 
60 
3 
64 
5^39 
4 
94 
Insoluble siliceous matter 
24 
98 
23 
56 
24 
93 
26-16 
28 
45 
100 
00 
100 
00 
100 
00 
100-00 
100 
00 
*Equal to tiibasic phosphate"! 
45 
97 
46 
43 
46 
•43 
45-19 
38 
61 
tEqual to carbonate of lime 
8 
07 
11 
93 
10-27 
8-95 
11 
66 
It will be seen that Boulogne coprolites contain about one- 
fourth their weight of insoluble siliceous matter, and consider- 
able proportions of oxide of iron and alumina. Like most 
coprolites, they also contain a good deal of fluorine. On the 
whole, they are poorer in phosphate of lime, and richer in oxide 
of iron and alumina, than Cambridge coprolites. They re- 
semble closely in composition the inferior phosphatic nodules 
which at the present time are dug up in Bedfordshire and in 
Norfolk. 
A superior variety of French coprolites is found in the valley 
of the Rhone, near Bellegarde, close to the Swiss frontier. 
The following analyses, made in my laboratory, represent 
the chemical character of two samples of such coprolites : — 
