Geological Conditions in Copford Brickfield. 429 



been done ; and with a view of an investigation, and its ap- 

 plication to a useful purpose in the coal districts, I laid a 

 communication before the Geological Society of London. 

 Shortly after that, the interesting work of Mr. Mammatt on 

 the coalfield of Ashby de la Zouch made its appearance ; 

 and in perusing it I was not a little pleased at finding that 

 the conclusions I had arrived at were the same as had resulted 

 from the experience of many years spent amongst the gloomy 

 recesses of the mine. I rather hastily adopted the opinion, 

 that the law would prove universal; but such appears evi- 

 dently not to be the case, although in small districts a great 

 regularity will generally be perceived : particular fossils always 

 occurring in one portion of a stratum, wherever it makes its 

 appearance, but in no other. When, however, we view the 

 same stratum in another part of the country, although the 

 same fossils are there, they do not appear to occupy the same 

 relative positions. 



Manchester, June 14. 1836. 



Art. IX. A Notice of the Geological Conditions ascertained from 

 Two Sections in the Brickfield, Copford, Essex; additional to 

 the Section, the Geological Conditions ascertained from ivhich 

 are stated in VII. 436 — 438. By John Brown, Esq. 



A fresh excavation having been made, in the course of the 

 last winter (1835-36), in a different part of the Copford 

 brickfield to the one of which an account is given in VII. 

 436 — 438. ; and, as there is a considerable variety in one of 

 the sections (the southern) especially, both in the mineral 

 properties of the beds and in their geological disposition, as 

 compared with those of the section above mentioned, I am in- 

 duced to send you the particulars of the case. 



The section given in VII. 436 — 438. is taken from the 

 western part of the field ; those following are taken from the 

 eastern and southern. 



The space of ground excavated is about 220 yards square ; 

 but the white marl and its accompanying shells are traced 

 east and west a mile distant from this spot. This formation 

 dips to the north beneath the meadows, at an angle of above 

 5 ft. in 60 yards. 



Section at the Eastern Part of the Field. — ] . Brown clay, 

 with rounded and angular flints ; boulders of quartz, trap, &c. : 

 from 1 ft. to 2 ft. thick. 2. Fragments of shells mixed with 

 sand and marl : from 2 ft. to 3 ft. 3. Brown clay mixed with 

 sand and marl, called by the workmen race : 1 ft. 4. Blue 



ii 3 



