474 Reviews — Beitrdge ziir Kenntnis der Kreidejiora. 



Attention must also be called to the rocks in the Northern High- 

 lands, which are believed to be hybrids between a scy elite and a 

 granite. In a very different field Dr. H. H. Thomas has brought the 

 wide range of his petrological knowledge to bear on the vexed 

 question of the origin of the famous " Blue Stones ", forming the 

 inner circle and inner horseshoe of Stonehenge ; twenty-nine out 

 of the thirty-four " foreign " stones there are identified as a spotted 

 diabase practically identical with that of the Prescelly Mountains 

 in Pembrokeshire, and three of the remainder appear to be a finely 

 banded rhyolite from the same locality. There can be little doubt 

 that they were transported to their present site by human agency. 



Valuable appendices as usual conclude the Summary. In one the 

 succession of Highland Schists displayed along the Banffshire coast 

 is described by Mr. Eead, who puts forward a tentative but highly 

 suggestive correlation of these with the schists of other Scottish 

 areas. Another by Mr. MacAlister deals with the production of tin ore 

 and other minerals in various parishes in Devonshire, and gives the 

 results in tabular form so as to bring out the economic value of 

 different tracts in the county. 



G. L. E. 



Beitrage zur Kenntnis der Kreideflora. I : User einige 



KREIDEPrLANZENVONSWALMEN(NlEDERLANDE). R. KrAUSEL. 



Mededeelingen van 'S Rijks Geologischen Dienst. Ser. A, No. 2, 



1922. 

 TN this paper Dr. Krausel gives a very clear and careful account of 

 -^ a small collection of fossil plants obtained at a depth of 653- 

 659 metres, from a boring at Swalmen, in Holland. Some of the 

 specimens were fortunately carbonized and amenable to treatment 

 by well-known chemical methods for demonstrating the structure 

 of epidermal cells and stomata. The descriptions and photo- 

 micrographs are good and m,ost of the photographs of the actual 

 specimens are satisfactory. The author shows an admirable restraint 

 in the identification of the plants, and does not employ names 

 implying affinities to recent genera without adequate evidence. 

 He errs, if he errs at all, on the side of caution ; the fern fragments 

 described, as Didymosauriis coynjptonicefolius Deb. and Ett., are almost 

 certainly Gleicheniaceous, and might well be included in Gleicheniles. 

 The beds are believed to correspond to the middle portion of the 

 Aachen sands, the flora of which was described many years ago by 

 Debey and Ettingshausen, and they are referred to the Senonian. 

 One species of fern is identified, the following conifers : Araucaria 

 crassifolia, Elatocladus elegans, Myriconia cyclotoxon, Sequoia 

 Reichenhachii, Sequoia sp. ; also three species of Dicotyledons, 

 referred to Myrica, and a few other Dicotyledonous leaves not 

 determinable with certainty. Associated with some of the cuticular 

 preparations are fungal hyphse, and in this connexion it is pertinent 

 to suggest that the dark spherical bodies shown in plate v on the 



