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Sihwa Lake is located at the Gojeongri, Hwaseong site in the Republic of Korea. The place where dinosaur egg fossils were discovered is reclaimed land on the south side of Sihwa Lake, which appeared after the construction of the Sihwa Lake Seawall. Gojeongri is the first location in Asia where a group of dinosaur egg fossils was discovered. The Asian countries in which the highest number of dinosaur eggs have been found are China and Mongolia. In China, however, a place where a group of dinosaurs had lain eggs has not yet been found. Recently, 198the second group-spawning site in Asia was discovered in Mongolia. Therefore, the Gojeongri site holds significant academic value as a globally-rare, group-spawning site.

The dinosaur egg fossils were found on twelve small islands that existed before the seawall was built. The fossil sites are distributed on the slopes and at the base of several small and large islands. Furthermore, there are now decks installed for visitors to look around the Mumyeongsom, Hahanyeom, Nudebawee, and Junghanyeom sites (Fig. 1).

Figure 1: Distribution map showing the dinosaur egg fossil sites in Hwasung Gojeongri.

The fossil sites, however, were submerged in seawater and are now located adjacent to industrial complexes and road networks, both of which emit toxic gases that cause acid rain that has a deadly effect on fossil conservation. As of today, 203 dinosaur egg fossils have been discovered at fifty-eight sites. Some basic research on the fossil sites has been conducted, according to which there are three types of dinosaur eggs: Faveoloothid, Dendroolithid, and Elongatoolith (Lee et al. 2000; Lee, 2003, Fig. 2). The type two dinosaur egg fossils, which were found only atthe Gaemesom site, have not been reported worldwide.

The first type of eggs are subspherical in shape, with an estimated maximum length of 13.5 cm and a width of 11.5 cm. The pores are large (0.34~0.45 mm in diameter), and are round or oval in cross section. The pore system is similar to multicanaliculate of the faveoloolithid-type eggs (Zhao and Ding, 1976).

The second type is smaller than the first type, and its pore system is similar to prolatocanaliculate of the dendroolithid-type eggs. The pore canals originate mainly in the interspaces between the shell units. These characteristics indicate that the dinosaur egg is a new dinosaur egg belonging to the dendrolithid-type (Lee, 2003).

The third type of eggs is represented by several pieces of eggshells in one location. These eggshells are 1 mm thick and have a linearituberculate surface texture, which differs from the sagenotuberculate ornamentation of the first egg type. This type of dinosaur egg is likely to be of theropod, and classed as an elongatoolith-type (Zhao and Ding, 1976).

On-site investigation revealed that the dinosaur egg fossils and the matrix rocks were damaged in several places. Because the fossils were exposed to rapid environmental changes and nature, various physical, chemical, and biological factors contributed to destroying the eggs’ original shapes. Therefore, it is necessary to investigate the fossil damage and to establish conservation measures in response to the rising attention toward accelerated damage of dinosaur egg fossils (Fig. 2).

Figure 2: Representative types of the dinosaur egg fossils from Hwasung Gojeongri. (left) Type 1, (middle) Type 2 and (right) Type 3.