natural history society of glasgow. 123 



November 28th, 1865. 

 Hugh Colquhoun, M.D., in the chair. Mr David Calderwood 

 was elected a resident member. 



SPECIMENS EXHIBITED. 



Mr E. A. Wiinsch exhibited a series of fossil trees recently 

 discovered by himself in the island of Arran. 



Mr John Young, in referring to Mr Wiinsch's interesting dis- 

 covery, stated that he had visited the district in company with 

 Mr Wiinsch, and made an examination of the strata in which the 

 plant remains had lieen found. These, he observed, are distinctly 

 stratified; and, although termed trappean ash, are completely 

 different from the ordinary trap-rocks of Arran. They are, in 

 fact, aqueous deposits, formed of materials derived from j)lutonic 

 sources, and are largely developed in many districts of central 

 Scotland. The present instance, however, is among the first in 

 which they have been found enclosing organic remains, or en- 

 tombing old forests of the coal period. Mr Young also stated his 

 conviction that aU these ash beds and ordinary bedded traps seen 

 upon this portion of the Laggan shore were formed contem- 

 poraneously with our lower coal measures, and were overlaid by 

 the carboniferous limestone series of the island. They are, there- 

 fore, of much greater age than the dykes and great sheets of 

 igneous trap which cut through and overlie the upper red sand- 

 stone of the south end of Arran. All the trees which he saw in 

 the ash beds referred to, retained their original erect position, 

 showing that the material had accumulated around their trunks 

 much in the same way as sandstones and shales are found 

 enveloping erect stems of fossil trees in the coal measures of other 

 parts of the world. It is probable, however, that the beds 

 accumulated much more rapidly than ordinary sedimentary strata. 

 The plants, as at present identified, belong to Lepidodendron, 

 Halonia, and Sigillaria; and as their original structure is wonder- 

 fully preserved, it is expected that these Arran fossil trees will 

 help to throw much light upon some of the vegetable organisms 

 of the coal period. 



Dr James Stirton exhibited specimens of Ghimmia subsquarrosa, 

 Wils., which he had gathered in August, 1864, on MoncriefF Hill, 

 near Perth, where it grows in considerable abundance. He stated 

 that Dr B. White had also, in May of this year, found the same 



