_Extent._--As to the actual dimensions of the terramara mounds, it is difficult to procure accurate measurements, for several reasons. In many instances they are either built over by modern buildings, or there is nothing to distinguish their _débris_ from the surrounding soil without making extensive excavations. Even when the site is a clearly-defined mound, as at Montale, one estimate may differ from another according as the area of the surrounding dyke is or is not included in the measurements. Generally speaking they are rectangular in form and, according to Chierici, their average superficial area is about seven acres. (B. 311, p. 105.) But their respective areas vary very much, as will be seen from the following stations, in addition to those already given, whose measurements have been accurately ascertained by competent authorities:-- Casaroldo (Parma), 200 by 160 by 3·70 mètres. (B. 297, p. 360.) Parma, 300 by 28 mètres. (Strobel e Pigorini, Seconda Relazione, p. 149.) Castiglione di Marano (Modena), 114 by 64, and 3 mètres thick. (B. 422, p. 19.) Pragatto (Bologna), 200 by 150, and 3 mètres thick. (B. 372, p. 138.) In his description of Bellanda (Mantua), Chierici observes that the bacino was a rectangle 96 mètres across, giving an area of about two acres, to which he adds "ampiezza ordinaria delle terremare." (B. 372, p. 80.) On the other hand, the two whose measurements have been accurately given by Parazzi, viz. Cogozzo and Casale Zaffanella, show a superficial area of only half this size, a fact which induced Parazzi to observe that the terremare in Viadana seemed to be smaller than those of Emilia and that at Bellanda. (B. 451, p. 4.) _Number._--The total number of terramara stations in the Po valley is over 100, which are thus (approximately) distributed among the provinces:--Parma, 30; Reggio, 25; Modena, 16; Bologna, 5 or 6; Mantua, about 20; and Brescia, 8.