A constitutional government is a system of governance in which the power is limited by law, as prescribed by a constitution. Let's analyze the given statements to determine which are correct:

1. It is a form of limited government: This statement is correct. Constitutional governments are characterized by limits on the powers of government officials and institutions, which are often laid out in a written constitution.
2. One where Constitution is the basis of public authority: This statement is also correct. In a constitutional government, the constitution acts as the supreme legal document, guiding all public authorities and determining how the state functions.
3. One where Monarch is the formal Head of the State: This statement is not correct. While a constitutional monarchy may have a monarch as the head of state, not all constitutional governments necessarily have a monarch. Constitutional governments can be republics without a monarch.
4. One where there is always universal adult franchise: This statement is not universally applicable to constitutional governments. While many modern constitutional democracies support universal suffrage, it is not a defining feature of all constitutional governments.

Based on the above analysis, the correct answer is the option 1 and 2 only.