Dr. Hans Reusch — A Quartz-Eyed-Gneiss. 223 



are composed. This rock is, I suppose, usually taken to be a granite, 

 but it is not an igneous rock. On the contrary, it is of sedimentary 

 origin, a felspathic sandstone (arkose or sparagmite) of very coarse 

 grain, almost bordering on a conglomerate. In the most 

 characteristic variety, from the palace of Sargon, the chief con- 

 stituent is white quartz in lumps varying in size between that of a 

 hazel-nut and an apple (see Fig. 1). These are embedded in a 

 cement of coarse-grained sparagmite. A notable peculiarity is that 

 the fragments of quartz have very irregular contours, giving the 

 appearance of an invasion of the larger fragments by the ground- 

 mass. In other varieties (Palace of Assurbanipal) the fragments of 

 quartz are smaller and may in some cases show no distinction from 

 the quartz-grains of the groundmass. 



This type of rock is an old acquaintance of mine, being a quartzose- 

 eyed-gneiss such as I have described from the neighbourhood of 

 Bergen, in Norway,^ but the oriental variety, "\vith larger quartz- 

 fragments, is a more glorious rock ; indeed, to a petrologist it is a 

 wonderful sight, a rock which has been preserved without weathering 

 in a remarkable wav for many centuries. 



cy ^ 



Fig. 2.— Folded granite veins in eyed-gneiss, Mesopotamia : one half natural 



size. 



There are only very indistinct traces of stratification or none at 

 all, but a study of the Norwegian locality has convinced me of the 

 sedimentary nature of the rock. The Bergen occurrence belongs 

 to the Ordovician system, which by regional metamorphism has 

 been converted into crystalline schists : the oriental rock is also 

 obviously metamorphic. The variety from the palace of Sargon is 

 seen to contain small granitic veins, closely folded as in Fig. 2. 



I do not know whether the place is known whence the ancients 

 got the material for these remarkable monuments. The rock is 

 so characteristic that there should be no difficulty in fixing the 

 locality. 



^ Reusch, Silurfossiler os pressede Konglomerater i Bergen sskifrene, 

 Kristiania, 1883, and (German translation) Die fossilienffihrenden 

 krystallinischen Schiefer von Bergen in Norwegen, ausg. von R. Baldauf, 

 Leipzig, 1883. 



