In the summer of 1879，I visited the province of Hitachi which is nearly 30 ri distant from Tokio,in order to collect mollusca in the lake of Kasumigaura. Along the coast, there exist numerous fossil remains of marine shells which show evidence that the lake had once been washed by the sea in past times. Bearing in mind this feature，I carefully examined the southen coast of this lake for shell heaps, and was finally rewarded by discovering three shell mounds on the top of a hill known as Okadaira ; and afterwards found still other mounds at several places not far from the one previously mentioned，viz. one at Kihara， two at Amiura，one at Shimadzu ; and on my return to Tokio， l again met with a single enormously large mound at Kitakatamura in Shimosa.
ln the winter of the same year in company with Mr.Iijima l again visited the same province in order to make still farther researches in regard to these mounds by the order of Mr.Kato President of Tokio Daigaku.
0n this occasion，we found a number of other mounds in the same province already mentioned before, but only one was completely examinede, and that was the Okadjra mound which was the largest and richest in ancient remains.
The contents of this paper are mainly confined to the contents of this mound，and one of our objects is to compare its features with those of the Omori She11 mounds，which have been well described and accurately figured by Prof. Edw.S.Morse in the first memoir of Tokio Daigaku.
0ur thanks are particularly due to the never failing advice of Prof. Edw. S.Morse.
0ur thanks are also due to Mr. M.Nishi for the determination of the nature of the stone implements and to Mr. H. Yoshida on chemical analysis, and lastly we are much indebted to our two sincere friends Mr.0.Taneda and Mr. M.Kikuchi for their kind assistance in many ways.
To the artists Mr.J.Nomura,Mr.M.lndo, and Mr.K.Watanabe, our thanks are specially due for the fidelity with which they have made the illustratious.
lst Sept. 2542(1882).