From Adolphe Tanquerey, A Manual of Dogmatic Theology, transl. by Rev. Msgr. John J. Byrnes, Desclee, New York, 1959, pp. 144-147. (All emphasis in the original.)
Tract IV, The Constitution of the Catholic Church.
CHAPTER II, THE AUTHORITY OF THE CHURCH ARTICLE I THE OBJECT OF THE POWER OR AUTHORITY OF THE CHURCH.
I. THE OBJECT OF THE DOCTRINAL MAGISTERIUM OF THE CHURCH .
249 State of the Question: This magisterium comprises all the rights which are necessary for teaching revelation and for guarding and defending the deposit of faith: for example, the power of defining infallibly, of setting up schools, of prohibiting certain books .
250 Thesis: The direct object of the infallibility of the Church includes all the religious truths and each individual truth which are formally contained in the sources of revelation; the indirect object embraces all those things which are required in order that the deposit of faith may be preserved entire. The first part of this thesis is de fide; the second part is certain.
251, 1. Explanation and proof of thesis. The Church was given infallibility for the purpose of protecting Christ’s teaching. And the object of this infallibility is either direct or indirect (Refer to thesis.)
a. It is a matter of faith that the Church is infallible in defining revealed truths (section 199). It is certain that it is infallible also in regard to truths that are closely joined to revealed truths. Otherwise the prerogative of infallibility would be purposeless and ineffectual since the Church would not be able to preserve, to defend, and to set forth the deposit of faith.
b. There is a vast distinction between the direct object of infallibility and the indirect object: if a truth formally revealed is defined by an infallible authority, it is the object of divine and of Catholic faith because this truth is believed on the authority of God Who is revealing. When infallible power is exercised in respect to truths connected with revelation, truths of this kind are the object of ecclesiastical faith only.
252, 2. The direct object of infallibility. This object is to define what has been revealed, to decide on the words of the definition, to establish the canon of Scripture, to condemn heresy, etc.
253, 3. The indirect object of infallibility. This comprises all that is intimately united with what has been revealed.
The Church is infallible:
a. In regard to truths of the natural order connected with dogma, which are necessary for protecting the deposit of faith; for example, the existence of God. 
b. The Church is infallible in regard to theological conclusions. (This is certain.) A theological conclusion is one which is certainly and manifestly deduced from two premises, one of which is formally revealed and the other is known naturally. It is necessary that the Church be infallible in regard to these theological conclusions in order to preserve the deposit of faith. If false theological conclusions are propagated, dogma is endangered because of the logical connection which the mind naturally perceives between the principles and the conclusions deduced from these principles. Whether theological conclusions are the object of divine faith we shall consider later in section 326.
254 c. The Church is infallible when it condemns a certain proposition with some doctrinal censure. A doctrinal censure is “a qualification or restriction which indicates that a proposition is opposed, in some way, to faith or morals”. It is de fide that the Church is infallible when she specifies that a doctrine is heretical; it is certain that the Church is infallible when she states that a doctrine approaches heresy, or that a doctrine errs in a matter of faith, or that it is false. All this is apparent from the consensus of theologians, and from the practice of the Church since its earliest days. The Church always made judgments against false propositions and also imposed upon the faithful the obligation of adhering to these judgments. Many assert that in all doctrinal censures the Church is infallible.
255 d. The Church is infallible in regard to dogmatic facts. A dogmatic fact is one which is so much connected with a doctrine of the Church that knowledge of it is necessary in order to understand the doctrine and to preserve it safely.
Dogmatic facts can be threefold: historical, doctrinal and hagiographical. Thus, dogmatic facts are the legitimacy of the Holy Pontiff, the ecumenical (universal) nature of a Council.
That the Church is infallible in regard to dogmatic facts is certain. For if the Church could make a mistake concerning the authority of the Holy Pontiff or of a Council, then there would always be grounds for doubting whether their decisions were infallible and accordingly for rejecting these decisions. So, too, for the question of whether a certain book contains orthodox teaching or heretical doctrine. Theologians commonly teach that the Church can infallibly determine what sense or meaning the words of a book convey once the context has been considered ; also whether this sense is orthodox or not. Otherwise, the Church would not be able to prevent heretics from spreading their errors and from avoiding condemnation. The heretics could say that the meaning of the book has not been correctly understood. Thus Clement XI declared "the sense (or meaning) conveyed by the five afore-said propositions of Jansenius’ book is condemned; this sense, as is evident, must be rejected and censured as heretical by all Christ’s faithful not only by word of mouth but also in the heart." 
256 e. The Church is infallible in regard to moral precepts since general laws for the universal Church cannot be in opposition to the natural or positive divine law, for the Church has received the obligation of leading souls to salvation. Therefore, it can enjoin nothing which has not been approved by God.
f. For a similar reason the Church is infallible in the matter of giving definitive approbation to a religious Order.
g. The Church is infallible in regard to canonization of saints, but not to beatification. This opinion is true and common: truly the Church cannot make a mistake in matters which concern a profession of faith and morals, when she is making known a definitive judgment and is imposing a precept on the faithful.
1. Major Synopsis, n. 818-826.
2. Code of Canon Law, can. 1322-1408.
3. Syllabus, prop. II D.B., 1711; Vatican Council, D.B., 1798.
4. QUILLIET, a. Censures doctrinales, in Dictionnaire de Theologie Catholique.
5. When propositions are condemned according to the meaning intended by the author, the condemnation results not from the subjective meaning which the author probably had in mind, but from the natural and obvious sense or meaning, as it is taken from the book itself after everything has been duly considered.
6. Denzinger, 1350.