HARD WICKKS S CIENCE- G OS SI P. 



^9 



caiilcsceiis, Bab.) should be searched for early in the 

 season. It is readily distinguished by the flrs. 

 being on scapes, instead of single peduncles ; it is 

 often misnamed in Herbaria, P. elaiior, Jacq., the 

 Bard field Oxlip is, however, a widely different 

 species. — y. F. R. 



Orchid Flowers. — Some misconception might 

 be felt, were no reply made to Mr. Robinson's note 

 in the January number of Science-Gossip, on 

 Orchis furpurea, militaris, and Simla. My own 

 observations on these three rare and beautiful plants, 

 as they grow in Kent, Bucks, and Oxen, are strongly 

 confirmatory of the opinion, usually held, that they 

 are distinct. When once known, they are distin- 

 guishable at a glance, and I have never met with 

 specimens that have given difficulty. Although the 

 three plants may be separated by the form and 

 coloration of the lip alone, there are various other 

 distinguishing characters which are almost entirely 

 ignored by Mr. Robinson. In " English Botany," 

 vol. iii., Dr. Bos well speaks of having seen forms inter- 

 mediate between 0. militaris and O. Simla in one 

 place only, and in this place he states that the two 

 species grow together. Dr, Boswell accordingly 

 attributes the occurrence of these forms to probable 

 hybridity, and when we consider the facilities for 

 crossing afforded by the peculiar mode in which 

 these plants are fertilised, but little doubt will be felt 

 that Dr. Boswell's solution is the correct one. 

 Possibly Mr. Robinson has chanced on a batch of 

 such hybrids ? I express no opinion on Mr. Robin- 

 son's plants, not having seen them ; my remarks 

 apply to the three species as they occur wild in this 

 country. — W. H. Beeby. 



GEOLOGY, &c. 



The Metamorphic Rocks of South Devon. — 

 At a recent meeting of the Geological Society a 

 paper was read on this subject by Professor T. G. 

 Bonney, F.R.S., Sec. G. S. He stated that the chief 

 petrographical problem presented by this district was 

 whether it afforded an example of a gradual transition 

 from slaty to foliated rocks, or whether the two 

 groups were perfectly distinct. He described the 

 coast from Tor Cross round by the Start Point to 

 Prawle Point, and thence for some distance up the 

 estuary leading to Kingsbridge. Commencing again 

 to the north of Salcombe, on the other shore of this 

 inlet, he described the coast round by Bolt ;Head, 

 and Bolt Tail to Hope Cove. These rocks, ad- 

 mittedly metamorphic, consist of a rather thick mass 

 of a dark mica-schist, and of a somewhat variable 

 chloritic schist, which also contains a good deal of 

 epidote. In the lower part of this are some bands of 

 a mica-schist not materially different from the upper 

 mass. It is possible that there are two thick masses 



of mica-schist, one above and one below the chloritic 

 schist ; but, for reasons given, he inclined to the view 

 that there was only one important mass, repeated by 

 very sharp foldings. The junction between the admit- 

 tedly metamorphic group and the slaty series at Hope 

 Cove, as well as that north of Salcombe, is clearly a 

 fault, and the rocks on either side of it differ materially. 

 Between the Start and Tor Cross the author believes 

 there is also a fault, running down a valley, and so 

 concealed. On the north side of this the rocks, 

 though greatly contorted and exhibiting such altera- 

 tions as are usual in greatly compressed rocks, cannot 

 properly be called foliated, while on the south side 

 all are foliated. This division he places near HoU- 

 sands, about half a mile to the south of where it is 

 laid down on the geological map. As a further 

 proof of the distinctness of the two series, the author 

 pointed out that there were clear indications that the 

 foliated series had undergone great crumpling and 

 folding after the process of foliation had been com- 

 pleted. Hence that it was long anterior to the great 

 earth movements which had affected the Palaeozoic 

 rocks of South Devon. He stated that the nature of 

 these disturbances suggested that this district of 

 South Devon had formed the flank of a mountain- 

 range of some elevation, which had lain to the south. 

 Of the foundations of this we may see traces in the 

 crystalline gneisses of the Eddystone and of the 

 Channel Islands, besides possibly the older rocks of 

 South Cornwall and of Brittany. He also called 

 attention to some very remarkable structures in the 

 slaty series near Tor Cross, which appeared to him to 

 throw light upon some of the structures observed at 

 times in gneisses and other foliated rocks. 



The Volcanic Group of St. David's. — This is 

 one of the most fruitful sources of geological contro- 

 versy at the present time. It has been still further 

 perplexed by additional views offered by Professor 

 Blake, in a paper just read before the Geological 

 Society. The result of the author's examination of 

 the rocks in the district of St. David's which have 

 been designated Dimetian, Arvonian, and Pebidian, 

 is that they belong to one volcanic series, whose 

 members are those usually recognised in eruptive 

 areas, and whose age is anterior to, and independent 

 of, the true Cambrian epoch. The independence of 

 this series and the Cambrian is shown by the nature 

 of the junction at all points of the circuit that have 

 been seen. 



Another Deep Well Boring near London. — 

 Another deep well boring, at Richmond, has thrown 

 extra light upon the ridge of ancient rocks which 

 previous borings in other places had brought to light. 

 Reckoning from the Thames level, the Richmond 

 well boring has now reached a greater depth by 150 

 feet than any other. The Eocene strata. Cretaceous, 

 Neocomean, and %1\ feet of the Great Oolite were 



