29 
But it is well known to mining engineers that of the faults affecting 
coal-bearing strata, some are pre-Permian and others post-Triassic ; and that 
the horizon at which the former cease to affect the strata, forms (for engineers) 
a far more serviceable datum line than any drawn from palzontological 
evidence only. 
Taking as our datum line the horizon thus indicated, and proceeding 
to the Southern Midlands and still further south, we find a series of beds 
into which faults affecting Upper coal-measure strata do not appear to 
penetrate —namely, the Permian breccia of Worcestershire, the dolomitic lime- 
stone of Bristol and Somerset, and possibly the higher of the two calcareous 
beds in the Enville district. Judged by this test, we shall probably find 
that we have a certain series of beds which still fall under Prof. Hull’s original 
classification (Permian beds of Salopian type) ; though, owing to the similar 
lithological characters of the two formations, a very large proportion of coal- 
measure strata was formerly wrongly included in this class. 
As, however, none of these beds nor beds of Zechstein are indicated in 
the Sealand borehole, near Chester, of which a section is here given below: 
SEALAND BOREHOLE, NEAR CHESTER. 
Thickness. Depth. 
ft. in. ft. in. 
ate a 79 6 ‘a 79 (6 
Bunter sandstone .. 56 .. 859 6 -. 939° 0 
Upper Coal Measures :— 
Red and grey shale with sandstone .. 32 
Limestone ae 
Estuarine and glacial 
oe oe oe 3 
Red shales aa ee se 26 
Grey sandstone ,. as ae * §9 
Grey limestone and spar ie bs I 
Grey sandstone .. oa Phares? 
Limestone s5 ve an I 
Grey sandstone—calcareous .. ae 2 
Limestone ar oe “ve an I 
Grey sandstone and shale aie be. 1.23 
Red sandstone .. ae ac ao 15 
Grey sandstone .. -- ve ee | 15 
Red and grey sandstone ac ae. 0 22 
Purple and blue shale .. Sc ‘ 
Dark grey and purple sandstone ricgwmee 
Purple and blue shale .. 
CO ONRADODR OCOMDWNWOTDDO ADDO AGCROAVO 

Grey limestone with black partings .. : 
Purple and blue shale with purple 
sandstone ., s0 os aa OG 
Reddish grey limestone... o. I 
Purple and blue shale with ironstone., 19 
Dark grey sandstone .. aE ee 45 
Reddish grey sandstone va sai 7G 
Shale with reddish grey sandstone ., 24 
Limestone—shaly in part =e guint 36 
Red and mottled shale containing 
ironstone .. an an Conran 
1,637 2 
and as Mr. De Rance has pointed out, no Zechstein Permian are elsewhere 
found south of a line drawn from Birkenhead to Nottingham, I think we 
may fairly conclude from the evidence that no Permian rocks, of either 
Zechstein or Salopian type, are likely to be met with in either Wirral or the 
western portion of the Cheshire plain. 
In passing, I wish to remark that it was a Chester gentleman, 
Mr. William Shone, F.G.S. (a Member of this Society), who had the honour 
of first determining the Carboniferous age of the deposits found below the 
Bunter rocks in this borehole. 
