Vallam is a panchayat town in Thanjavur district in the Indian state of Tamil Nadu

Vallam has three rock-cut shrines belonging to Pallava era. Although these cave shrines have some of the best sculptures, they remain unknown to the public. All the three rock-cut shrines are excavated in a hillock. Even though it is not clearly known who built these cave shrines, it is clear that they were built during the period of Mahendravarma Pallava (580-630 CE).

Cave #1: 

This is the uppermost rock of the hill. One can reach this cave temple by climbing around 100+ steep steps. As this temple is still used for the purpose of worship, the entire cave is covered by iron grill from all the sides.

This cave shrine is dedicated to Lord Shiva. Lord Shiva is named as Vedanteeswarar in this temple. The Goddess of the temple is Gnanambikai who is facing the eastern direction. Although Shiv Linga is placed in the small sanctum sanctorum, all other idols including Gnanambikai are found in the same shrine outside the sanctum sanctorum. The other idols that are found in the temple are Selva Vinayak (Ganesha), Muthukumaraswami along with his consorts Valli and Devasena, Dakshinamurthy, Chandikeswarar, Nagaraja and Bhuvaneswari. There is also a Nandi idol facing the main shrine. All these idols would have been installed at a later period and they do not belong to the period of this cave shrine.

The highlight of this cave is two rock-cut relief images of Dwarapalaks standing on either side of the entrance of the main shrine.

Outside to this cave shrine, this is a big rock cut image of Ganesha is found. This image is very beautiful and displays some of the rare features. As the trunk of Ganesha (the elephant God) is turned towards right, he is called as ‘Valampuri Vinayak’. He has four hands and seated in simhasana (royal throne). His one hand is resting on a small platform whereas his other arm is resting on his thigh. His upper arms carry a broken lotus stalk and another unclear material. The overall posture of Ganesha is rare and cannot be found anywhere else.

Cave#2: 
This cave is located below the upper cave and is found on the same boulder. This cave temple doesn’t have any pillar or mandapa. Moreover, this is not under worship nowadays. This shrine has two relief images of Dwarapalaks. The main shrine has a damaged Shiv Linga idol. Two small relief images of Jyestha and Ganesha are also found here.

Cave #3: 

This is the northern most caves and is found on the way to the other two caves. This cave shrine is dedicated to Lord Vishnu. This shrine doesn’t have any pillar or mandap. It is a small cell carved vertically on the rock. The shrine has Vishnu along with his two consorts, Sridevi and Bhoodevi. He is named as ‘Karivaradaraja Perumal’. These three idols appear to be later addition. There are two Dwarapalaks relief images outside the cave shrine which date back to the original period. The relief image of Vishnu Durga is also found outside the shrine.

Source:

http://indiancolumbus.blogspot.com/2011/10/pallava-era-cave-temples-of-vallam.html