OBSERVATIONS ON THE STRUCTURE OF ROWLEY RAG. 261 
71°C., and a small portion of malt in tepid water is added; 
in a few minutes the starch becomes limpid and clear, and 
glucose may he tested for by Feliling’s copper solution. 
3C 6 H l0 O 6 + H 2 0 = C 6 H l2 0 6 + 2C 6 H l0 O 6 
Glucose. Dextrin. 
Starch is insoluble in cold water and alcohol. Lime forms a 
weak compound with it, and free iodine and bromine com¬ 
bine with it to form coloured compounds. The iodine reaction 
is always used to show the presence of starch in vegetable 
tissue, and further it is used very extensively by chemists as 
an indication of the termination of certain reactions in the 
quantitative estimation of substances where potassic iodide is 
reduced. 
DEEP BORING NEAR BIRMINGHAM. 
A boring which is being executed at King’s Heath by 
Messrs. Le Grand and Sutcliff, of 100, Bunliill Row, London, 
is of considerable interest as affording a good section of the 
division of the Triassic strata. 
Drift ------ 62 feet. 
Red marls ----- 160 ,, 
Ditto, with gypsum - - 123 ,, 
Red and blue marls, with gypsum - 97 ,, 
Thus the total depth now reached is 442 feet. In the letter 
from the firm by whom the boring is being executed (and to 
whom I am much indebted for the particulars), it is pointed 
out that the range of the gypsum bands, over a thickness of 
220 feet (or rather less when the dip of the strata is taken 
into account), is somewhat unusual. I shall hope to be able 
to give particulars of the completion of this boring in another 
number. 
W. J. H. 
SOME RECENT OBSERVATIONS ON THE 
STRUCTURE OF ROWLEY RAG.* 
BY T. H. WALLER, B.A., B.SC. LOND. 
The microscopical structure of the great mass of basic 
igneous rock which we locally call Rowley Rag was described 
by Mr. Allport in the “ Quarterly Journal of the Geological 
Society” for 1874, p. 548, so that on the general subject I 
* Transactions of the Birmingham Natural History and Micro¬ 
scopical Society, read before the Meeting March 24th, 1885. 
