THE 



ESSEX NATURALIST 



BEING THE 



Journal of tbc lEsdcy jfielb Club 



FOR 1893. 



THE NEW RAILWAY BETWEEN UPMINSTER 

 AND ROMFORD. 



BOULDER CLAY BENEATH OLD RIVER GRAVEL AT 

 HORNCHURCH. CONCLUSIONS THEREFROM. > 



By T. V. HOLMES, F.G.S., M.A.I., etc. 

 [Read February 21st, jSgj-] 



T^HE new railway from Upminster to Romford is the most 

 northerly portion of the line connecting Grays Thurrock with 

 Romford. In The Essex Naturalist for 1890 (vol. iv., p. 143) I 

 gave some account of the sections then visible in the most southerly 

 part of this railway. I there stated that south of Back Lane Chalk 

 appeared, while between Back Lane and the stream known as the 

 Mardyke it became covered by the Lower Tertiary formations, the 

 Thanet Sand and Woolwich Beds, the overlying London Clay being 

 seen on the northern side of the Mardyke Valley, and thence 

 constituting the oldest rock visible anywhere, not merely along the 

 course of the railway, but anywhere southward of the upiise of the 

 Chalk and Lower Tertiaries in northern Essex. 



But a glance at the section given in The Essex Naturalist 

 (vol. iv., p. 146), showing the arrangement of the beds just mentioned 

 from West Thurrock to the northern flank of the valley of the 

 Mardyke, reveals the fact that the surface of the high ground, both 



I For the block of the section and m.ap illustrating this paper, the Editor is indebted to the 

 courtesy of the Council of the Geological Society. 



B 



