The Bhutanatha main group (700–725 CE) is the older set of Hindu shrines to the east of the Agastya Teertha. The oldest temple in this group is the main large temple. It has a gudha-mandapa with four massive central pillars (partly octagonal, cubical and rounded on a lathe). This mandapa connects to a smaller square-plan sanctum with a Shiva linga. On the top of the sanctum is the Dravida-style
tritala superstructure (three storeys). The lower part consists of a padabandha and kumbha. The vimana walls has karnas with
Brahmakanta-style pilasters. The wall's nasis depict heads of kinnaras and gandharvas. The second storey of the superstructure repeats the lowest larger storey, and the third storey is half of the second in size, and again repeats the same elements in a rhythmic form. A square vedi topped with a short shikhara completes the superstructure. The image
niches on the wall of the shrine and the hall are now empty though some decorative elements like
makharas (mythical beast) with long tails still remain. The mandapa has
jali (perforated windows for light into the inner mantapa). On either side of the foot of the shrine doorway is an image of goddess Ganga on her vehicle, the
makara, on the right, and on the left, that of goddesses
Yamuna riding the tortoise. There is no dedicatory block upon the lintel. Other artwork found nearby include Ganesha and Mahisasuramardini. A notable feature here is the inscription on the outer wall of the temple, which announces a gift from a Paingara family to the Sridharbuteswara (likely an epithet of the deity). This inscription can be dated to about the late 9th century. This suggests the main temple was in active use at the time. The porch pillars have a square cross section that transforms into an octagonal cross section. Outside, there is a stepped
ghat for the devotees and pilgrims. The smaller shrines are ruined and were added later, likely through late 8th century. To the east of the complex, on a boulder, are four Shaiva reliefs with unusual architectural details – these are impressions of four architectural styles of Shiva sanctum with panchakuta superstructure set on a square plan. These can be dated to the late 7th or early 8th century, and help establish that this temple complex was a Shaiva complex from its origin. To the north of the main temple is a small shrine which, proposed Henry Cousens in 1923, was originally consecrated for
Vishnu. At some point, the temple was adopted by the followers of
Lingayatism who built an outer hall and installed a
Nandi (vehicle of Shiva) and a Shiva
linga inside the sanctum. ==Mallikarjuna group==