1849.] BROWN ON THE SYDNEY COAL-FIELD. 115 



Sutural angle about 95°. Basal angle 100°. Greatest diameter 

 f of an inch. 



Found in limestone of the subcretaceous series at the village of 

 Sarjento-mor, six miles north of Coimbra. 



Plate XIII. fig. 4 a. Exterior. 



Fig. 4 h. Internal cast. 



Fig. 4 c. Section. 



EXPLANATION OF THE PLATES. 



PLATE XIL 



Fig. 1. Nerinsea nobilis. Fig, 3. Nerinsea Titan. 



Fig 2. Nerinsea turbinata. 



PLATE XIII. 



Fig. L Nerinsea annulata. Fig. 3. Nerinsea Olisiponensis. 



Fig. 2. Nerinsea Eschwegii. Fig. 4. Nerinsea Conimbrica. 



2. Section of the Lower Coal-Measures of the Sydney Coal- 

 FiELD, in the Island of Cape Breton. By Richard Brown, 

 Esq. 



[Communicated by the Secretary.] 



The coal-measures of Nova Scotia Proper have been carefully exa- 

 mined and described by Sir Charles Lyell. Mr. Logan has also 

 published a " Section of the Nova Scotia Coal-Measures, as developed 

 at the Joggins in the Bay of Fundy," which appears to have attracted 

 much attention ; but the Cape Breton coal-fields, in every point of 

 view the most important in British America, appear to have been 

 almost wholly neglected by geologists. I have been for some years 

 engaged in collecting materials for a description of the Sydney coal- 

 field, but seeing no immediate prospect, amidst the engrossing duties 

 of an arduous profession, of completing such an extensive work, I 

 have concluded to submit to the Society a detailed section of the 

 lower part of the productive coal-measures, as developed on the 

 shores of Sydney Harbour, under the impression that it will furnish 

 many valuable facts and data calculated in an eminent degree to elu- 

 cidate the origin of the coal beds, and at the same time to assist geo- 

 logists in instituting a comparison with the Bay of Fundy section, 

 from which it will be found to differ in at least one very important 

 feature, to which I shall refer more particularly in the sequel. 



This coal formation, as has been already stated in vol. i. p. 23 of 

 this Journal, consists of the following group of strata : — 



4. The productive coal-measures. 



3. A thick deposit of sandstone. 



2. Limestones and shales, occasionally containing beds of gypsum. 



1 . A coarse conglomerate. 



The lowest member of this group (1), the representative probably 

 of the old red sandstone of Europe, crops out from beneath the car- 

 boniferous limestone at the head of the north-west branch of Sydney 

 Harbour, where it consists of thick beds of conglomerate alternating 



