626 Correspondence — Mr. G. H. Morton. 



very mucli like to know wbich are the fossils of tlie strata under- 

 lying the Dictyonema Schists to which Mr. Hicks refers as being 

 " Silurian in type and not Cambrian." To me the scanty knowledge 

 of the fauna of these beds does not seem sufficient to warrant, per se, 

 a conclusion as to their age. Fortunately, the sequence of the strata 

 gives a good clue. The Dictyonema Schists of Sweden are very 

 nearly related to the Olenus Schists, which they always immediately 

 overlie, in some places seemingly without any sharp line of demarca- 

 tion. The Olenus Schists of Sweden are exactly equivalent to the 

 Lingula Flags of England, and therefore the rocks underlying the 

 Eussian Dictyonema Schists cannot, at least, be younger than the 

 Lingula Flags, if we are to judge from the paleeontological evidences, 

 and from the sequence of the strata. 



Mr. Hicks says that if I could only be brought to recognize his 

 views of the gradual encroachment of the sea from a western or 

 south-western direction over the European area, I should certainly 

 feel none of those difficulties which now occur to my mind. It may 

 be so, but it is my habit, in scientific investigations, first to make 

 myself acquainted with facts, and then to proceed to generalizations. 

 Even if Mr. Hicks may think it more proper and easy first to form 

 theories,' and then to "dispose of" the facts, so that they may not 

 interfere with the theories, I cannot help thinking that the opposite 

 way is the true one, and that the knowledge of facts must forego the 

 forming of theories. As I — and probably also your readers — now 

 begin to feel tired of the paper war with Mr. Hicks, I shall not 

 hereafter pursue it. G. Linnaesson. 



SECTION" OF BOULDER-CLAY, NORTH DOCKS, LIVERPOOL. 



Sir, — As a natural consequence of the two recent letters in the 

 Geological Magazine, in reference to the Boulder-clay recently 

 exposed in the new dock works to the north of Liverpool, I beg to 

 hand you a copy of the Eeport I sent, as a member of the Committee, 

 to the Eev. H. W. Crosskey, F.G.S., Secretary of the Boulder Com- 

 mittee of the British Association. 



" Eecently very extensive excavations have been made in the 

 Boulder-clay at Bootle, a northern suburb of Liverpool. The site is 

 intended for new docks, and extends along the Eiver Mersey, being 

 reclaimed from the shore within the tidal range. The following is a 

 section of the Drift deposits that have been exposed continuously 

 over many acres ; but the thickness of each varies considerably ac- 

 cording to position, and the Middle Sands and Gravels often thin 

 out and leave the Upper Boulder-clay reposing on the Lower 

 Boulder-clay. 



1. Sand and Silt of the old shore 17 feet. 



2. Upper Boulder-clay 15 ,, 



3. Middle Sands and Gravels 6 „ 



4. Lower Boulder-clay 6 „ 



(Bunter Sandstone) 



" The whole of these subdivisions repose, each in succession, on the 



Bunter Sandstone at that part of the section nearest the old coast-line. 



" The Lower Boulder-clay contains a much greater quantity of 



