138 eeport— 1879. 



made (at the instance of the Dudley and Midland Geological Society) 

 that it might be examined. 



This is the largest erratic block of slate that has yet been seen in the 

 district, and it is associated with very numerous boulders of granite and 

 felsite. 



3. Mr. E. B. Marten has called attention to a boulder recently dis- 

 covered by Mr. Beale in a watercourse running nearly due N. and S. 

 near Moseley Hole, and the Wolverhampton, Willenhall, and Walsall 

 turnpike-road, and an accommodation road across the collieries from the 

 Osier Bed Furnaces and Slow Lane, to Bilston. It is in the line of the 

 third ' h,' in the words ' Stow Heath Furnace,' and the letter ' P,' of 

 ' The Plough ' on the one-inch Ordnance Map, No. 62, S. W. Lichfield. 



The boulder is composed of granite, and measures about 4' 75 feet 

 every way. Its weight is probably about three tons. Its shape is sub- 

 angular, the angles being, with one exception, slightly rounded, but this 

 exception is as sharp and clean as though the block had just been detached 

 from its parent rock. The soil in which the boulder occurs is of a 

 gravelly and sandy nature, containing some pebbles bearing the well- 

 known indentations peculiar to, and characteristic of, the pebble beds of 

 Biinter. Its height is 420 feet above the sea-level. 



4. At Manor Green, half-a-mile S. of Walsall, in a field near the Old 

 West Bromwich road, a block of felsite stands erect, like a pillar. It 

 measures 4 - 5 x 4'5 x 2 feet. 



Mr. L\ Mackintosh reports on the origin of the so-called 'green- 

 stone M boulders around the estuaries of the Mersey and the Dee (the 

 occurrence of which has previously been recorded in these Reports by 

 Mr. G. Morton, F.G.S.), to the following effect : 



While tracing Criffel boulders southwards, he has observed 'green- 

 stone' (or as they are locally called, ' whinstone') boulders and pebbles 

 apparently on their way south, along with the granite on the west coast 

 of Cumberland, N. of Whitehaven. Between the Scottish and Cum- 

 brian coasts and the peninsula of Wirral (between the estuaries of the 

 Mersey and the Dee) the course of these boulders is lost under the Irish 

 Sea. The area around the Mersey estuaries in which the boulders are 

 very much concentrated is intensely striated, and nearly all the striae 

 point divergently to the S. of Scotland, i.e. between N. 15° W. and N. 

 45° W. 



On the most extensively glaciated rock surface (successively exposed 

 and demolished by quarrying operations near St. James' Church, 

 Birkenhead), the larger grooves point to between 25° and 30° W. of N. 



A large ' greenstone ' boulder has been found at Crosby, near Liver- 

 pool, resting on a perfectly flat glaciated rock-surface with strias pointing 

 N. 40° W. 



Additional presumptions in favour of the Scottish derivation of these 

 boulders may be found (1) in the fact that nearly all of these boulders 

 consist of basic rocks similar to some at least found in the S. of Scotland ; 

 and (2) in the extent to which they are concentrated and almost entirely 

 locally limited to the peninsula of Wirral and the neighbouring part of 

 Lancashire. This last circumstance shows that they could not have come 

 from widely different points of the compass, while it is as probable as the 



1 The word ' greenstone ' is retained in the text because the boulders have fre- 

 quently been described under this name. It is, however, inaccurate. Most of the 

 boulders in question are dolorites or diorites. 



