222 The Scottish Naturalist. 



and other stones are mere varieties of the same chemical 

 material, stained by the presence of iron, magnesia, &c. 



The peculiar "weathering" of trap is due not to any propensity 

 that it has for assuming odd forms, the forms were assumed on its 

 solidification. The plane surfaces are the first to disintegrate, 

 being exposed to the percolation of water. "Sand" or "earth- 

 pipes " are sometimes seen in positions that have been exposed 

 to the solvent power of rain. 



VAKIOUS NOTES. 



We have much pleasure in informing our readers that the Rev. J. 

 Fergusson, New Pitsligo, and Mr. John Roy, Aberdeen, are preparing a 

 " Guide to the Botany of the North-East of Scotland," which is intended to 

 include the district between the Tay and the Spey. It will contain full in- 

 formation of the localities, local names, etc. , both of flowering plants and 

 cryptogams. It is also intended to give descriptions of species found in the 

 district, when they are not described in British books. It is proposed to 

 publish it by subscription, and we understand that it will probably be ready 

 in the course of 1875. 



We have received the programmes of an International Botanical Con- 

 gress, and of an International Horticultural Exhibition, which are to take 

 place at Florence under the auspices of the " Societe Royale Toscane 

 d' Horticulture " between the nth and 25th of May, 1874, and under the 

 Presidency of Professor Parlatore. Some twenty-two themes are proposed 

 for discussion at the Congress. Among them we especially notice one on 

 the possibility of establishing a rational distinction between the groups 

 known by the names of species, race, variety ; another on the character and 

 origin of island floras ; and another on the character and origin of. 

 alpine floras, and particularly on the causes which limit their ex- 

 tension. At the Exhibition a large number of gold, silver, and bronze 

 medals are offered as prizes. From what we hear, a concourse of the most 

 distinguished botanists and horticulturists in Europe may be expected, and 

 Ave should advise any of our readers who meditate a visit to Italy next 

 spring to visit Florence during the Congress, to which any botanist will be 

 admitted by ticket (which may be had from the President for the asking 

 before March 1st). Italian will be the official language, but any member 

 can use at all times his mother-tongue if he prefers to do so. Botanical ex- 

 cursions in the neighbourhood of Florence, and to Pisa, etc., are also planned, 

 and we have no doubt that any foreign botanist who presents himself will 

 have "a good time of it." 



We have also received a valuable contribution on the subject of Zoological 

 Nomenclature, by Dr. Sharp. We hope to be able in next number to notice 

 this pamphlet at greater length. 



"Monograph of the Collembola and Thysanura," by Sir J. 



