194 CEMENT MATERIALS AND INDUSTRY. Lbdll. 243. 
Analysis of limestone from Bayport. 
[Analyst, J. W. Langley.] 
Silica 3. 330 ^ 
Oxide of iron and alumina 1. 334 
Carbonate of magnesia 944 
Carbonate of lime - 91. 538 
Phosphorus and sulphur Trace. 
Organic matter and loss 2. 854 
100. 000 
(Quicklime, 51.29.) 
Analysis of limestone from Bellevue. 
[Analyst, Carl Rominger.] 
Carbonate of lime 96. 00 
Carbonate of magnesia 1. 00 
Hydrate of iron oxide 50 
Insoluble residue 1. 50 
99.00 
Analysis of limestone from Portage River. 
[Analyst, Carl Rominger.] 
Carbonate of lime 96. 90j 
Carbonate of magnesia 1. 00 
Alumina and iron 70 
Insoluble residue 1. 40 
99.00 
The limestone of the "Michigan series" contains layers that are high in magnesia 
or are otherwise unfavorable for cement making, but in spite of this the formation 
is evidently worthy of careful attention from persons interested in the industry 
under review wherever it occurs near deposits of clay or shale and is suitably 
situated in reference to transportation facilities, etc. 
All of the limestones referred to above are of marine origin and usually contain 
fossils, among which coral is frequently conspicuous. The rocks are usually com- 
pact and hard, and if employed in the manufacture of Portland cement must be I 
crushed and ground to a fine powder. Except for the expense thus involved they 
are in certain instances as favorable for the use indicated as the marls described 
below. 
MARL DEPOSITS. 
Russell describes the marl deposits as follows: 
Some idea of the abundance and wide distribution of marl deposits in the southern 
peninsula may be obtained from the map [PI. VIII], on which those it has beeni 
convenient to locate are indicated. This is by no means a complete irdex of the 
total number of marl deposits that occur in the area represented, as it has not been 
found practicable to make a detailed survey for the purpose of mapping them. It is 
safe to say that those shown on the map are probably less than one-fourth of the- 
total number that exists in the southern peninsula. Those indicated on the map, 
with possibly a few exceptions, have an area in excess of 50 acres, and an average 
depth of 10 feet or more.« The marl beds of Michigan only are considered in this 
a In the compilation of the data shown on the map, I have been assisted by Dr. A. C. Lane, State 
geologist, Prof. C. A. Davis, of Alma College, and others. [Note by Russell.] 
