Vol. 50.] ANNIVERSARY ADDRESS OF THE PRESIDENT. 12 9 



Doubtless we have not heard the last of Dartmoor, but meanwhile 

 geologists may take comfort in the reflection that the latest writer 

 on the subject sees good reason to endorse the views of De la Beche. 



There is yet one more burning question in connexion with the 

 county of Devon, viz. the age and character of the Start (or Bolt) 

 Schists — a problem which, is perhaps, more difficult of solution 

 than that of the Dartmoor granite. Supplementary to Prof. 

 Bonney's well-known paper, written ten years ago, are some notes 

 on the Metamorphic Bocks of South Devon by Miss Baisin, who 

 endeavoured to show that the slaty beds to the northward do not 

 pass into the mica- and chlorite-schists, but are separated from the 

 latter by a line of faults. Some petrographical details were given , 

 and an attempt was made to determine the succession of chlorite- 

 mica- and micaceo-chloritic schists around the Salcombe estuary. 



It is nearly seven years since Miss Baisin's paper was read, and 

 the subject has not again been mooted in the Quarterly Journal^ 

 but papers have been published in the Transactions of the Devon- 

 shire Association bearing upon this matter, and lately Mr. Hunt has 

 taken up the cudgels against the views of Prof. Bonney and Miss 

 Baisin. On the whole, there is at present a reaction against the 

 notion that the metamorphic rocks of South Devon are of Archaean 

 age or even older than the adjacent Devonian. Mr. Ussher, indeed, in 

 his Geological Map of West Somerset, Devon, and Cornwall, issued 

 in 1892, 1 boldly colours the whole as Lower Devonian — a plan 

 which at least saves the trouble of having to trace a boundary-line. 



It would be exceeding my prescribed limits to notice at any 

 length Mr. Hunt's paper published about a year and a half ago in 

 the Geological Magazine. 2 His object was to endeavour to ascer- 

 tain what affinities can be detected between the metamorphic rocks 

 of South Devon and the slates, grits, and volcanic rocks which lie 

 to the northward of them ; the green rocks being compared with 

 the volcanics, the mica-schists with the slates, and the quartz- 

 schists with the fine grits or sandstones. Commencing with the 

 latter, he observes that the undoubted Devonian sandstones may 

 be traced into the undoubted metamorphic quartz-schists by four 

 independent lines of enquiry, viz. by way of iron-ores, tourmaline, 

 mica, and quartz. In making these comparisons he suggests 

 that, with some exceptions, the mica in both the Devonian and 

 metamorphic rocks is, or was originally, detrital, the deposition of 



1 Proc. Somerset. Archseol. Soc. vol. xxxviii. 



2 Vol. for 1892, p. 241. This paper was published in three ^successive 

 numbers, viz. those for June, July, and August. 



