394 MR. B. THOMPSON ON LANDSCAPE MARBLE. [Aug. 1 894. 



on the surface are often curiously interlaced, giving rise to the 

 so-called ' rustic-work ' for which the stone was chiefly quarried. 

 Owen speaks most enthusiastically of the ' rustick ' thus : — " When 

 I have viewed the whole thus nearly, it appeared not a piece of 

 common rustick, but an imitation of something much more elegant. 

 The depths of the hollows between the rising parts is varied, and 

 their form different, in so strange a manner, that no two are at 

 all alike : and the waving and curdlings of the surface in the 

 raised parts is such, that every one of them seems a piece of 

 rustick in miniature, the whole surface being formed, like that of 

 the mass, into risings of the most elegant kind, and irregular hollows 

 between them" (p. 166). Owen also refers to the scaling (p. 167). 



4. The interior of the stone is characterized by dark markings, 

 which pervade the stone between certain limits, and have much 

 the appearance of foliage. 



The markings rise from a more or less stratified base, spread out 

 as they rise, and terminate upwards in the wavy banded portion of 

 the limestone ; the whole varying from 1 to about 9 inches in 

 thickness. 



As the markings are disposed more in a vertical direction than 

 laterally, in order to show them the stone is usually cut and polished 

 at right angles to the stratification. 



5. Two landscapes are shown in some specimens, one above the 

 other, but each arising from a distinct dark layer. A very fine 

 specimen with a double landscape is to be seen in the Museum of 

 Practical Geology, Jermyn Street. 



II. Specific Description of the Landscape Marble. 



Under this head I propose to describe more minutely the 

 characteristics of the specimens in my own possession (though I 

 believe them to be quite ordinary examples), because some im- 

 portant points of structure do not appear to have been noted by 

 previous observers. 



6. The whole thickness of the stone may be regarded as made up 

 of three distinct portions, the upper and lower being striated and 

 the middle irregular, through the interposition of the arborescent 

 markings (see figs. 1 & 2, pp. 395, 397), and in the specimen that I 

 shall particularly refer to, fig. 1, the general curvature of each 

 layer, as well as the striae in it, is just about the same, the inner 

 edge being an arc of a circle of about 4| inches radius, and the outer 

 edge, approximately, an arc of a circle of 7| inches radius. 1 



7. The lower portion of the stone is about li in. in thickness, 

 and at first looks as though very sharply divided into two by 

 difference of sediment, and a line of cleavage ; neither of these 

 surmises, however, can be retained after a microscopic examination. 



The lowest (A) is light yellowish-brown in colour, and longi- 



1 Mr. H. B. Woodward observes that the lower surface of the limestone is 

 even, though sometimes in small masses of the rock it is gently curved. 



